Explanation / Rationale

Test cases TC1, TC2, TC3 and TC4 cover, respectively, rules R2, R3, R7 and R6 in the decision table.
a) Is correct. The conditions “66-year-old”, “unregistered” and “no experience” match rule R4, which is not covered by the existing test cases, so after adding this test case, the decision table coverage will increase
b) Is not correct. The conditions “55-year-old”, “unregistered” and “2 years of experience” match rule R2, already covered by TC1. So adding this test case will not increase the coverage
c) Is not correct. The conditions “19-year-old”, “registered” and “5 years of experience” match rule R6, already covered by TC4. So adding this test case will not increase the coverage
d) Is not correct. The existing test cases cover only 4 out of 7 columns of the decision table. The coverage can be increased by adding test cases that cover yet uncovered columns, that is, R1, R4 and R5

Explanation / Rationale

a) Is not correct. To ensure successful reviews, it's important to secure management's support for the review process, however that does not mean that they should participate as reviewers
b) Is correct. To ensure successful reviews, it's important to break the work product into parts that are small enough to be reviewed in a reasonable timescale to prevent reviewers from losing focus during individual review or review meetings
c) Is not correct. To ensure successful reviews, it's important to clearly define objectives and measurable exit criteria, without evaluating participants
d) Is not correct. To ensure successful reviews, it's important to break down the review into smaller chunks to prevent reviewers from losing focus during individual review or review meetings. So you should not plan to cover one document per review

Explanation / Rationale

In the three-point estimation technique:

E = (optimistic + 4*most likely + pessimistic)/6

E = (2+(4*11)+14)/6 = 10

Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct

Explanation / Rationale

a) Is correct. Performing only black-box testing does not provide a measure of actual code coverage. White-box coverage measures provide an objective measurement of coverage and provide the necessary information to allow additional tests to be generated to increase this coverage, and subsequently increase confidence in the code
b) Is not correct. This statement is correct, but it has nothing to do with black-box testing
c) Is not correct. In general there are no subsumes relationships between white-box and black-box techniques
d) Is not correct. White-box techniques are used to design tests based on the test object itself, while black-box techniques are used to design tests based on the specification. Therefore, there is no relation between coverage items derived from these two types of techniques

Explanation / Rationale

a) Is not correct. This should be a team activity and not overruled by one team member
b) Is correct. If test estimates are not the same, but the variation in the results is small, applying rules like “accept the number with the most votes” can be applied
c) Is not correct. There is no consensus yet as some say 13, others say 8
d) Is not correct. A feature should not be removed only because the team cannot agree on the test estimates

Explanation / Rationale

Considering each of the listed task descriptions:

1. The quality characteristics to be evaluated and the exit criteria are selected - (Planning (C): Defining the review scope, purpose, work product to be reviewed, quality characteristics to be evaluated, areas of focus, exit criteria, supporting information such as standards, effort, and timeframes.)
2. Everyone has access to the work product - (Review initiation (B): Ensuring all participants have access to the work product and necessary resources, and clarifying their roles and responsibilities.)
3. Anomalies are identified in the work product - (Individual review (A): Evaluating the work product's quality, identifying and logging anomalies, recommendations, and questions using review techniques like checklist-based and scenario-based reviewing.)
4. Anomalies are analyzed and discussed - (Communication and analysis (D): Analyzing and discussing each anomaly, determining its status, ownership, and required actions, and making review decisions, normally in a meeting. This could include determining the need for a follow-up review.)

Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct. The correct match is: 1C, 2B, 3A, 4D

Explanation / Rationale

“Small garden” and “large garden” can go only with “ground floor”, so we need two test cases with “ground floor” which cover these two “garden type” partitions.
We need two more test cases to cover the two other “floor” partitions and a remaining ”garden type” partition of “no garden”.
We need a total of four test cases:

TC1 (ground floor, small garden)
TC2 (ground floor, large garden)
TC3 (first floor, no garden)
TC4 (second or higher floor, no garden)

Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. One of the purposes of retrospectives is to identify potential process improvements, which, if put into practice, should result in the quality of future outputs of the development process (test objects) being higher. So, this is likely to occur as a result of a retrospective
b) Is not correct. A benefit of retrospectives for testing includes increased test efficiency through process improvements. So, this is likely to occur as a result of a retrospective
c) Is correct. Participants at retrospectives typically include testers, developers, architects, product owners, and business analysts, but end users are rarely invited or attend these meetings – and they are also unlikely to receive any reports from these meetings. So, it is very unlikely that they will learn and understand more about the development and test processes through retrospectives
d) Is not correct. A benefit of retrospectives for testing includes improved quality of testware (including automated test scripts) through joint reviews with developers. So, this is likely to occur as a result of a retrospective

Explanation / Rationale

a) Is not correct. While the sentence is true, it does not provide much value for the developer
b) Is correct. From the test results it seems that the system ignores duplicates and sorts the list disregarding the repetitions. This is probably the cause of failures in TC3, TC4, TC5. Such information may help the developer to find the defect and fix it more efficiently
c) Is not correct. The system does not fail in sorting negative numbers. The problem is rather in disregarding duplicates
d) Is not correct. The test cases TC3, TC4 and TC5 fail, but we aren’t aware that the test cases have any defects

Explanation / Rationale

a) Is correct. The number of defects found is related to the test object quality
b) Is not correct. This is the measure of the test efficiency not the test object quality
c) Is not correct. The number of test cases executed does not tell us anything about the quality; test results might do
d) Is correct. defect density is related to the test object quality
e) Is not correct. Time to repair is a process metric. It does not tell us anything about the product quality

Explanation / Rationale

a) Is not correct. The fundamental strength of white-box test techniques is that the entire software implementation is taken into account during testing
b) Is not correct. White-box coverage measures provide an objective measure of coverage and provide the necessary information to allow additional tests to be generated to increase this coverage
c) Is not correct. White-box test techniques can be used to perform reviews (static testing)
d) Is correct. This is the weakness of the white-box test techniques. They are not able to identify the missing implementation, because they are based solely on the test object structure, not on the requirements specification

Explanation / Rationale

a) Is correct. This is something that can (and should) be checked before the code is submitted to version control
b) Is not correct. This is something that can be checked after step (2) is performed, because merge conflict reporting can be done after the code is submitted and merged
c) Is not correct. This fits better as the entry criterion for step (3)
d) Is not correct. This fits better as the exit criterion for step (3)

Explanation / Rationale

The domain for the password length has three equivalence partitions:

• passwords too short {0, 1, …, 4, 5}
• passwords OK {6, 7, …, 11, 12}
• passwords too long {13, 14, …}

To achieve full coverage for 3-value BVA we need to test the following values:

0, 1, 4, 5, 6, 7, 11, 12, 13, 14.

Since 2-value BVA is already covered, this means that we have already tested the passwords of length:

0, 5, 6, 12 and 13.

This means that the additional lengths that need to be covered to move from 2-value to 3-value are:

1, 4, 7, 11 and 14.

Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct

Explanation / Rationale

Considering each of the listed review types:

1. Technical review - This type of review is performed by technically qualified reviewers and led by a moderator. The objectives are to gain consensus and make decisions on technical problems while also evaluating quality and building confidence in the work product, generating new ideas, motivating and enabling authors to improve, and detecting anomalies
2. Informal review - The main objective is to detect anomalies. The process is not defined and does not require formal documented output
3. Inspection - This is the most formal review type, and it follows the complete generic review process. The primary objective is to find the most anomalies, and other objectives include evaluating quality and building confidence in the work product, motivating and enabling authors to improve, and collecting metrics that can be used to enhance the software development life cycle (SDLC), including the inspection process. The author cannot act as the review leader or scribe
4. Walkthrough - Led by the author, this type of review serves various objectives such as evaluating quality and building confidence in the work product, educating reviewers, gaining consensus, generating new ideas, motivating and enabling authors to improve, and detecting anomalies. Reviewers might perform an individual review before the walkthrough, but this is not mandatory

A. Includes objectives such as gaining consensus, generating new ideas, and motivating authors to improve (A)
B. The main objective is detecting potential defects and it generates no formal documented output (D)
C. The main objective is detecting potential defects and it requires metrics collection to support process improvement (C)
D. Includes objectives such as educating reviewers, gaining consensus, generating new ideas and detecting potential defects (B)

Thus:
a) Is not correct
b) Is correct. The correct match is: 1A, 2D, 3C, 4B
c) Is not correct
d) Is not correct

Explanation / Rationale

i. Is true. The SDLC has an influence on the test process
ii. Is false. The number of defects detected in previous projects may have some influence, but this is not as significant as i, iii and iv
iii. Is true. The identified product risks are one of the most important factors influencing the test process
iv. Is true. Regulatory requirements are important factors influencing the test process
v. Is false. The test environment has no significant influence on the test process

Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

Consider:

i. It is a Project risk
ii. It is a Product risk
iii. It is a Product risk
iv. It is a Project risk
v. It is a Product risk

Thus:
a) Is correct
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

The following three transitions:

“REQUESTING -> CONFIRMED”
“WAITING LIST -> CONFIRMED”
“WAITING LIST -> END”

cannot appear in the same test case, which suggests that at least three test cases are required. All the other transitions can appear in combination with one or more of these three transitions, so we need a minimum of three test cases. In fact, only three sequences are possible:

TC1: START (Room request) → REQUESTING (Available) → CONFIRMED (Pay) → END
TC2: START (Room request) → REQUESTING (Not available) → WAITING LIST (Available) → CONFIRMED (Pay) → END
TC3: START (Room request) → REQUESTING (Not available) → WAITING LIST (Cancel) → END

Thus:
a) Is correct
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

Test TC 001 must come first, followed by TC 002, to satisfy dependencies. Afterwards, TC 003 to satisfy priority and then TC 004, followed by TC 005.
Thus:
a) Is correct
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is correct. This test covers two acceptance criteria: one about editing the document and one about saving changes
b) Is not correct. Acceptance criteria cover the editor activities, not the content owner activities
c) Is not correct. Scheduling the edited content for publication may be a nice feature, but it is not covered by the acceptance criteria
d) Is not correct. Acceptance criteria state about reassigning from an editor to the content owner, not to another editor

Explanation / Rationale

Considering each of the listed test activities and their tasks:

A. Test analysis - To identify the features that require testing, the test basis is analyzed and defined as test conditions, which are then prioritized along with related risks. During this test analysis, defects in the test basis are typically uncovered, and the test object's testability may also be assessed. (Task 4)
B. Test design - Involves using test conditions to create test cases and other necessary testware, such as test data requirements and test charters for exploratory testing. (Task 1)
C. Test implementation - Test procedures, such as manual and automated test scripts, are created from test cases and may be assembled into test suites. Test procedures are prioritized and arranged in a test execution schedule. (Task 3)
D. Test completion - Occurs at project milestones, such as release, end of iteration or end of test level. Testware is identified and archived or handed to the appropriate teams for reuse, the test environment is shut down, and the test activities are analyzed for lessons learned and future improvements. (Task 2)

Thus:
a) Is not correct
b) Is correct. The CORRECT match is: 1B, 2D, 3C, 4A
c) Is not correct
d) Is not correct

Explanation / Rationale

Considering:

• The test basis for acceptance testing is the user’s business needs (1D)
• Communication between components is tested during component integration testing (2B)
• Failures in logic can be found during component testing (3A)
• Business rules are the test basis for system testing (4C)

Thus:
a) Is correct
b) Is not correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is correct. This test case is related to acceptance criteria 2 and 3, because we check if we can set price range (acceptance criterion 2) and if the results update dynamically after adjusting the price range filter (acceptance criterion 3)
b) Is not correct. This test case is not related to any of the acceptance criteria. It checks if the filter dynamically sets the default minimum and maximum price range, and not that a customer can do it
c) Is not correct. This test case is not related to any of the acceptance criteria. It checks the currency exchange feature, which is not discussed in this user story
d) Is not correct. This test case is not related to any of the acceptance criteria. It checks the application’s compatibility with different browsers, which is not discussed in this user story

Explanation / Rationale

a) Is not correct. A member without a missed deadline can get a discount and a gift T-Shirt after 15 bicycle rentals
b) Is not correct. A member without a missed deadline can get a discount but no gift T-Shirt until they rented a bicycle 15 times
c) Is not correct. Non-members cannot get a discount, even if they did not miss a deadline yet
d) Is correct. No discount as a non-member that has also missed a deadline, but only members can receive a gift T-Shirt. Hence, the action is not correct

Explanation / Rationale

a) Is not correct. Testing quadrants group test levels and test types separately according to several criteria. They do not represent any combinations of test levels and test types and they are not related to any location within a software development lifecycle. Both test levels and test types are treated separately in the testing quadrants model
b) Is not correct. Testing quadrants group test levels and test types according to several criteria. They do not describe the degree of granularity of individual test types performed at each test level. Such a model, regarding the test levels, is called the test pyramid
c) Is not correct. The statement is wrong, because in general any test type can be performed at any test level
d) Is correct. The testing quadrants group test levels, test types, activities, test techniques and work products in Agile software development. In this model, tests can be business facing or technology facing. Tests can support the team (i.e., guide the development) or critique the product (i.e., measure its behavior against expectations). The combination of these two viewpoints determines the four quadrants

Explanation / Rationale

a) Is not correct. Scope creep is an example of a project risk related to technical issues
b) Is correct. Poor architecture is an example of a product risk since it refers to a product characteristic
c) Is not correct. Cost-cutting is an example of a project risk, related to organizational issues
d) Is not correct. Poor tool support is an example of a project risk related to technical issues
e) Is correct. Response time too long is an example of a product risk since it refers to a product characteristic

Explanation / Rationale

a) Is correct. The primary benefit of independence in testing is that testers are more likely to identify different types of failures and defects compared to developers, due to their varied backgrounds, technical viewpoints, and potential biases, including cognitive bias. However, the main disadvantage of independence in testing is that testers may become isolated from the development team, leading to communication problems, a lack of collaboration, and potentially an adversarial relationship, with testers being blamed for delays and bottlenecks in the release process
b) Is not correct. A developer’s familiarity with the code does not mean that they rarely find defects in it, instead this familiarity means they can efficiently find many defects in their own code. And, rather than developers and testers having a shared background, developers having a different background to testers is normally cited as the reason that testers and developers find different kinds of defects
c) Is not correct. Testing can be conducted at different levels of independence, ranging from no independence for the author to very high independence for testers from outside the organization. In most projects, multiple levels of independence are utilized, with developers performing component and component integration testing, the test team performing system and system integration testing, and business representatives performing acceptance testing. So, testers can be in the developer’s team and do not need to come from outside the organization. Knowledge of the application domain will change from case-to-case and is not dependent on the level of independence
d) Is not correct. Testing can be conducted at different levels of independence, ranging from no independence for the author to very high independence for testers from outside the organization, with testers from outside the developer’s team generally more independent than testers from within the team. However, there is more reason to believe that testers from outside the team are likely to be more isolated from the developers and so are more likely to be blamed for delays in product release

Explanation / Rationale

a) Is not correct. Although it is correct to say that in Agile software development, some of the test management tasks may be handled by the Agile team itself, the testing role is not primarily the responsibility of a single individual from outside the team. Instead the testing is more likely to be performed by various team members following the whole-team approach
b) Is not correct. The test management role primarily involves activities related to test planning, test monitoring and control, and test completion. So, although this statement is partially correct, it is wrong to say that the testing role is primarily responsible for test monitoring and control
c) Is correct. In Agile software development, some of the test management tasks may be handled by the Agile team itself. However, for test activities that span multiple teams within an organization, test managers outside of the development team may perform these tasks
d) Is not correct. The test management role primarily involves activities related to test planning, test monitoring and control, and test completion, while the testing role is primarily responsible for the technical and engineering aspects of testing, such as test analysis, test design, test implementation, and test execution. Thus the test management role is not normally responsible for test analysis and test design, although it is correct to say that the testing role is primarily responsible for test implementation and execution

Explanation / Rationale

a) Is correct. Test automation can provide measures that are too complicated for humans to derive, such as white-box test coverage measures for all but the most trivial code
b) Is not correct. By using test tools the responsibility for the testing is NOT shared with the tool vendor as the vendor is not involved in the testing, and it is the tester’s responsibility. The only possible responsibility that could be assigned to the tool vendor is if the tool fails to work as expected and provides incorrect test results
c) Is not correct. Testers still need to perform critical thinking when analyzing anomalies in the test results to determine their likely cause
d) Is not correct. Neither testers nor tools can generate test cases simply from an analysis of the program code as the code is the implementation and provides no information on the expected results, which will need to come from another part of the test basis, such as the design specification

Explanation / Rationale

a) Is not correct. The document does not refer to the test object’s internal structure but specifies the desired behavior of the test object. Therefore, white-box test techniques will not be helpful in designing test cases
b) Is correct. The document is a requirement that specifies the desired behavior of the test object. Therefore, the most suitable test techniques in this case are the black-box test techniques (e.g., Boundary Value Analysis or Decision Table Testing)
c) Is not correct. Although experience-based test techniques can be used to design test cases based on this document, black-box test techniques will be more suitable. The document describes a precise business rule and, in addition, wording like "exceeds $100" suggests the existence of important equivalence partition boundaries that should be tested using black-box test techniques like boundary value analysis
d) Is not correct. Risk-based test techniques are not a recognized type of test technique

Explanation / Rationale

a) Is not correct. Decision table testing is a black-box test technique, so it is specification-based, not structure-based – the test cases are not based on the decisions in the source code. In branch testing, the test cases are derived from knowledge of the control flow of the test object
b) Is not correct. Anticipation of potential defects is used in error guessing (an experience-based test technique), not in branch testing (a structure-based technique). In decision table testing, the test cases are derived from the specification that describes the business logic
c) Is not correct. If a test case is based on the knowledge of the control flow of the test object, it is a white-box test technique. Decision table testing is typically based on an analysis of business logic, so it is a black-box test technique. In branch testing, test cases are not derived from the specification – this would make it a black-box test technique. Branch testing is a white-box test technique, where test cases are derived based on the source code structure
d) Is correct. Decision table testing is a black-box test technique, so it is based on an analysis of the specified behavior of the test object without reference to its internal structure. Therefore, the test cases are independent of how the software is implemented. Branch testing is a white-box test technique, so test cases are based on an analysis of the test object’s internal structure and processing. As the test cases are dependent on how the software is designed and coded, they can only be created after the design or implementation of the test object

Explanation / Rationale

Only third-party executable code cannot be reviewed.
Thus:
a) Is not correct
b) Is not correct
c) It is correct
d) Is not correct

Explanation / Rationale

Considering each of the listed risks and their mitigations:

1. Long system responses (1) can be tested in performance testing (B)
2. Changes of consumers’ preferences (2) are usually out of our control, so usually we accept this risk (A)
3. Flooding of the server room (3) can cause significant loss, so we should transfer the risk, e.g., by buying an insurance policy (D)
4. That patients above a certain age receive inaccurate reports (4) suggests a potential boundary problem, which can be effectively detected with techniques like BVA (C)

Thus:
a) Is not correct
b) Is not correct
c) Is correct. The correct combinations of risk and mitigation are: 1B, 2A, 3D and 4C
d) Is not correct

Explanation / Rationale

a) Is not correct. DevOps generally increases the visibility of non-functional quality characteristics, such as performance and reliability
b) Is not correct. Automated processes like continuous integration/continuous delivery (CI/CD) used in DevOps facilitate stable test environments
c) Is not correct. Automated processes like CI/CD used in DevOps generally reduce the need for manual testing
d) Is correct. DevOps implementation can pose several risks and challenges, including the need to define and set up the delivery pipeline, introduce and maintain CI/CD tools, and establish and maintain test automation

Explanation / Rationale

i. Is true. Having domain knowledge is an important tester skill
ii. Is false. This is a task of the business analyst together with the business representative
iii. Is true. Being a good team player is an important skill
iv. Is false. Planning and organizing the work of the team is a task of the test manager or, mostly in an Agile software development project, the whole team and not just the tester
v. Is true. Critical thinking is one of the most important skills of testers

Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. The benefits of retrospectives include team bonding and learning from sharing issues, and better collaboration between developers and testers through reviewing and improving working practices. Calling out individuals who a team member may feel did not fully contribute to achieving quality as required by the whole-team approach will not contribute to this team bonding and collaboration
b) Is correct. During the retrospective, the group discusses what aspects of the project were successful and should be retained, as well as areas that could be improved, and how to do so
c) Is not correct. The benefits of retrospectives are based on increased effectiveness and efficiency through process improvements; they are not an opportunity to let off steam and criticize management and customers. Also, the results are recorded, usually in the test completion report, so anything said in the meeting could be read by other stakeholders
d) Is not correct. Retrospectives are meetings that are typically held at the end of an iteration where team members will focus on discussing quality-related issues that have occurred in the current iteration. They are not used for making plans or technical decisions for the next iteration; this would be done in the iteration planning meeting at the start of the next iteration

Explanation / Rationale

a) Is not correct. This is a new product. You probably do not have a checklist yet and test conditions might not be known due to missing requirements
b) Is not correct. This is a new product. You probably do not have enough information to make correct error guesses
c) Is correct. Exploratory testing is most useful when there are few known specifications and/or there is a pressing timeline for testing
d) Is not correct. Branch testing is time-consuming, and your management is asking about some test results now. Also, branch testing does not involve domain knowledge

Explanation / Rationale

a) Is not correct. ‘The capability of generating test cases without access to the test basis’ is not possible. The generation of test cases by either testers or tools requires access to the test basis
b) Is not correct. ‘The achievement of increased coverage through more objective assessment’ is not a direct benefit of test automation. Test automation will provide more objective assessment of coverage, however that objective assessment will not increase the coverage. Only by using the results of the coverage to write further test cases can the coverage possibly be increased
c) Is not correct. ‘The increase in test execution times available with higher processing power’ is a contradictory statement as higher processing power would normally reduce execution times, and increased execution times are not a benefit as the testing would take longer
d) Is correct. The prevention of human errors through greater consistency and repeatability is a benefit of test automation as test automation cannot suffer from human errors. For instance, it means that tests are consistently derived from requirements, test data is created in a systematic manner, and tests are executed by a tool in the same order with the same frequency

Explanation / Rationale

The ‘exhaustive testing is impossible’ principle is concerned with the fact that it is not feasible to test every possible variation of test inputs in all different circumstances, except in trivial cases. Instead, testing utilizes test techniques, test case prioritization, and risk-based testing to sample from the set of possibilities and focus testing efforts.
a) Is not correct. The principle states that it is not feasible to test everything except in trivial cases. Testing everything would require testing every possible variation of test inputs in all different circumstances, which is generally infeasible as there will be a practically infinite number. Testing every possible specified output will not address this problem as the relationship between inputs and specified outputs can be different for each test object. Sometimes there may be a practically infinite number of possible specified outputs (e.g., when there are several variables representing real numbers), whereas at other times there may be just two specified outputs, such as with a single variable that can be either true or false
b) Is not correct. The principle states that it is not feasible to test every possible variation of test inputs in all different circumstances. This is because for non-trivial systems there is a practically infinite number. Therefore, in practice, documenting all possible test input variations would be impractical as it would take an infinite length of time
c) Is not correct. Starting testing as early as possible with reviews and other static testing approaches will not address the problem of there being too many possible test cases. The ‘early testing saves time and money’ principle is concerned with fixing defects early on to prevent the occurrence of subsequent defects in derived work products, thereby reducing costs and the likelihood of failures
d) Is correct. The use of equivalence partitioning and boundary value analysis to generate test cases is one way to address the principle as these test techniques provide a systematic way to derive a finite subset of all possible test cases

Explanation / Rationale

a) Is not correct. QA concentrates on process improvement and implementation, using a preventive approach to avoid errors and defects, while testing is a form of QC that is used to detect defects
b) Is correct. QC aims to achieve appropriate levels of quality by focusing on identifying and correcting product defects. Testing is a significant part of QC and helps to uncover these defects
c) Is not correct. Although testing is a significant part of QC and helps to uncover defects, other (non-testing) techniques utilized in QC include formal methods like model checking and proof of correctness, as well as simulation and prototyping
d) Is not correct. QA concentrates on process improvement and implementation, using a preventive approach to avoid errors and defects, while testing is a form of QC that is used to detect defects

Explanation / Rationale

a) Is correct. The client is in a different location and time zone, so it may be difficult to communicate face-to-face
b) Is not correct. Dashboards are usually available to any user at any time, so the difference in time zones will not be as much of a hindrance to communication as verbal, face-to-face communication
c) Is not correct. Although the time difference between Europe and America is several hours, and this may cause some inconvenience, it's certainly not as great as with communicating face-to-face
d) Is not correct. Video conferencing tools are a convenient means of communication. Although communication between Europe and America during working hours usually requires one party to connect in the very early or very late hours, this is not as much of an inconvenience as verbal, face-to-face communication