Explanation / Rationale

a) Is not correct. The rule-oriented format includes formats like bullet point verification lists or tabulated forms of input-output mappings, explicitly showing the rules to be followed. Given/When/Then is a scenario-oriented format because it describes a scenario to be verified
b) Is correct. This is a Given/When/Then format, which is scenario-oriented
c) Is not correct. There no "product-oriented" format of acceptance criteria
d) Is not correct. There is no "process-oriented" format of acceptance criteria

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

a) Is not correct. In most cases both black-box test techniques and experience-based test techniques can be used for the same test objects
b) Is not correct. Both black-box test techniques and experience-based test techniques can be used at all test levels
c) Is correct. Black-box test techniques (also known as specification-based techniques) are based on an analysis of the specified behavior of the test object without reference to its internal structure. So, the test basis is usually a specification. Experience-based test techniques effectively use the knowledge and experience of testers for the design and implementation of test cases. This means that the tester, when designing tests, may not use the specification at all
d) Is not correct. Experience-based test techniques can detect defects that may be missed using black-box (and white-box) test techniques. Hence, experience-based test techniques are complementary to black-box test techniques and white-box test techniques and both black-box test techniques and experience-based test techniques can be used in all SDLCs

Explanation / Rationale

a) Is not correct. Retrospectives are more useful for identifying improvement opportunities and have little importance for clients
b) Is not correct. Business representatives are not giving feedback about the product itself. Therefore, there is no financial gain to the organization
c) Is correct. Regularly conducted retrospectives, when appropriate follow up activities occur, are critical to continual improvement of development and testing
d) Is not correct. Courage and respect are values of Extreme Programming and are not closely related to retrospectives

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

a) Is not correct. It is more often used in behavior-driven development (BDD)
b) Is not correct. It is the description of test-driven development (TDD)
c) Is correct. In acceptance test-driven development (ATDD) tests are written from acceptance criteria as part of the design process
d) Is not correct. It is used in BDD

Explanation / Rationale

a) Is not correct. The miscalculation of bonuses is a failure by the system, not a defect
b) Is not correct. The system not suitably supporting disabled users is a failure which eventually results in a fine, but the fine itself is not a failure (it appears to be the correct functioning of the regulatory system)
c) Is correct. The error is made by the programmer and this mistake is caused by them working under severe time pressure, which is the root cause of the subsequent defect
d) Is not correct. The poor design of the user interface, which does not suitably address disabled users, is a design defect caused by the designer error. Thus the design of the user interface includes a design defect not a designer error

Explanation / Rationale

a) Is not correct. Coverage is always defined as the percentage of the covered elements. Therefore, it cannot exceed 100%
b) Is correct. If the statements executed by T1 and T2 were disjoint, the coverage of the test suite {T1, T2} would be 105%, which is impossible (see answer a). Therefore, at least 5% of executable statements must have been executed by both T1 and T2
c) Is not correct. Statement coverage does not tell us anything about the number of non-executable statements in the code
d) Is not correct. Even if a test suite achieves full statement coverage, this does not imply achieving full branch coverage

Explanation / Rationale

a) Is correct. Since 100% statement coverage is achieved, every statement, including the ones with defects, must have been executed and evaluated at least once
b) Is not correct. Coverage depends on what is tested, not on the number of test cases. For example, for code “if (x==0) y=1”, one test case (x=0) achieves 100% statement coverage, but two test cases (x=1) and (x=2) together achieve only 50% statement coverage
c) Is not correct. If there is a loop in the code there may be an infinite number of possible paths, so it is not possible to execute all the possible paths in the code
d) Is not correct. Exhaustive testing is not possible (see the seven testing principles section in the syllabus). For example, for code “input x; print x” any single test with arbitrary x achieves 100% statement coverage, but covers one input value

Explanation / Rationale

a) Is not correct. In the whole-team approach, testers play a vital role by sharing their testing expertise with the team and guiding product development. They collaborate with other team members to achieve the desired quality levels and work with business representatives to create acceptance tests. Testers also partner with developers to determine the optimal test strategy and automation approaches
b) Is correct. By leveraging the diverse skill sets of each team member most effectively, the whole-team approach fosters superior team dynamics, promotes robust communication and collaboration, and generates a synergistic effect that benefits the entire project
c) Is not correct. The whole-team approach allows any team member with the requisite skills and knowledge to undertake any task, thus specialist team members are not an advantage of this approach
d) Is not correct. There is no specific guidance on the optimum size of teams using the whole-team approach, and there is no suggestion that larger teams are better

Explanation / Rationale

Considering each of the listed tool categories:

i. Collaboration tools – facilitate communication. Communication does not include the facilitation of test execution
ii. DevOps tools - support the DevOps delivery pipeline, workflow tracking, automated build process(es) and CI/CD. The delivery pipeline and CI/CD both include the facilitation of test execution, such as component testing for CI
iii. Management tools – increase the test process efficiency by facilitating management of the SDLC, requirements, tests, defects and configuration. The management of these items does not include the facilitation of test execution
iv. Non-functional testing tools – allow the tester to perform non-functional testing that is difficult or impossible to perform manually. Non-functional testing can include both static testing and dynamic testing, including test execution
v. Test design and implementation tools – facilitate generation of test cases, test data and test procedures. The generation of this testware does not include the facilitation of test execution

Thus:
a) Is not correct
b) Is correct. Both DevOps tools (ii) and Non-functional testing tools (iv) facilitate test execution
c) Is not correct
d) Is not correct

Explanation / Rationale

Consider:

i. Is true. Faster product release and faster time to market is an advantage of DevOps
ii. Is false. Typically, we need less effort for manual tests because of the use of test automation
iii. Is true. Constant availability of executable software is an advantage
iv. Is false. More regression tests are needed
v. Is false. Not everything is automated and setting up a test automation framework is expensive

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

Explanation / Rationale

a) Is not correct. Impediments to testing can be high level and business-related, so this is an important piece of information for business stakeholders
b) Is correct. Branch testing is a technical metric used by developers and technical testers. This information is of no interest to business representatives
c) Is not correct. Test progress is project related, so it may be useful for business representatives
d) Is not correct. Risks impact product quality, so it may be useful for business representatives

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

The equivalence partitions are: {…, 99, 100}, {101, 102, …, 198, 199}, {200, 201, …}.
Thus, there are 4 boundary values, which are: 100, 101, 199 and 200.
In 2-value BVA, for each boundary value there are two coverage items (the boundary value and its closest neighbor belonging to the adjacent partition). As the closest neighbors are also boundary values in the adjacent partition, then there are just four coverage items.

Thus:
a) Is not correct. Only 100 and 200 are valid coverage items for 2-value BVA, so we achieve 50% coverage
b) Is not correct. Only 100 and 200 are valid coverage items for 2-value BVA, so we achieve 50% coverage
c) Is not correct. Only 100 and 101 are valid coverage items for 2-value BVA, so we achieve 50% coverage
d) Is correct. 101, 199 and 200 are valid coverage items for 2-value BVA, so we achieve 75% coverage

Explanation / Rationale

a) Is not correct. The fact that the requirement about the system’s performance comes directly from the client and that the performance is important from the business point of view (i.e., high priority) does not make these tests functional, because they do not check “what” the system does, but “how” (i.e., how fast the orders are processed)
b) Is correct. This is an example of performance testing, a type of non-functional testing
c) Is not correct. From the scenario we do not know if interacting with the user interface is a part of the test conditions. But even if we did, the main test objective of these tests is to check the performance, not the usability
d) Is not correct. We do not need to know the internal structure of the code to perform the performance testing. One can execute performance efficiency tests without structural knowledge

Explanation / Rationale

a) Is not correct. 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. Evaluating the test basis for defects and the test object for testability are tasks performed as part of test analysis, so it is likely they are tasks performed by the testing role
b) Is not correct. 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. Defining the test environment requirements is a task performed as part of test design, so it is likely to be a task performed by the testing role
c) Is not correct. 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. Assessing the testability of a test object is a task performed as part of test analysis, so it is likely to be a task performed by the testing role
d) Is correct. The test management role primarily involves activities related to test planning, test monitoring and control, and test completion. Thus, creating the test completion report, which is the prime output from the test completion activity, is likely to be a task performed by the test management role

Explanation / Rationale

a) Is correct. In sequential development models, in the initial phases, testers participate in requirement reviews, test analysis, and test design. The executable code is usually created in the later phases, so dynamic testing cannot be performed early in the SDLC
b) Is not correct. Static testing can always be performed early in the SDLC
c) Is not correct. Test planning should be performed early in the SDLC before the test project begins
d) Is not correct. Acceptance testing can be performed when there is a working product. In sequential SDLC models the working product is usually delivered late in the SDLC

Explanation / Rationale

a) Is correct. A fundamental strength that all white-box test techniques share is that the entire software implementation is taken into account during testing, which facilitates defect detection even when the software specification is vague, outdated or incomplete. This means white-box testing can find defects such as an extra feature added to the code (either accidentally or deliberately) that is not supposed to be there, which black-box testing cannot detect
b) Is not correct. The fact that the coverage can be precisely defined is not the right reason. The achieved level of coverage would have much more impact than the possibility to measure the coverage
c) Is not correct. If the software does not implement one or more requirements, white-box testing is unlikely to detect the resulting defects of omission
d) Is not correct. While this is true, this is not the right answer, because there is no connection between the capability to be used in both static testing and dynamic testing and the claim that white-box testing facilitates defect detection with poor specifications

Explanation / Rationale

a) Is not correct. The test automation approach is defined by testers with the help of developers and business representatives
b) Is not correct. The test strategy is decided in collaboration with the developers
c) Is not correct. Testers, developers, and business representatives are part of the whole team approach
d) Is correct. Testers will work closely with business representatives to ensure that the desired quality levels are achieved. This includes supporting and collaborating with them to help them create suitable acceptance tests

Explanation / Rationale

a) Is correct. For a complex configuration item (e.g., a test environment), CM records the items it consists of, their relationships, and versions
b) Is not correct. CM tools do not execute test cases and do not calculate coverage
c) Is not correct. A CM tool is not a license management tool
d) Is not correct. CM tools do not generate test data

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

a) Is not correct. Strong communication skills, active listening, and teamwork abilities enable a tester to interact effectively with all stakeholders, however a deep knowledge of a variety of computer games that allowed them to get on well with one developer is not an example of a generic skill useful to testers
b) Is correct. Domain knowledge that can be used to understand and communicate with end-users and business representatives is one of the generic skills required by testers. A tester with experience as a pilot would make them better able to appreciate the acceptance criteria for the helicopter control system
c) Is not correct. Although programming skills could be considered as technical knowledge which can increase efficiency when utilizing some test tools, it is unlikely that these skills would improve their communication with business analysts
d) Is not correct. Although thoroughness, attention to detail, curiosity, and a methodical approach to identifying hard-to-find defects are all useful generic skills for testers, it is doubtful they would be generating test cases prior to starting exploratory testing. This is because one of the main tenets of exploratory testing is that the test cases are generated during the testing, not scripted in advance

Explanation / Rationale

a) Is not correct. Quality should be the responsibility of everyone working on the project and not the sole responsibility of the test team
b) Is not correct. First, it is not a benefit if an external test team does not meet delivery deadlines, and second, there is no reason to believe that external test teams will feel they do not have to meet strict delivery deadlines
c) Is not correct. It is bad practice for the test team to work in complete isolation, and we would expect an external test team to be concerned with changing project requirements and communicating well with developers
d) Is correct. Specifications are never perfect, meaning that assumptions will have to be made by the developer. An independent tester is useful in that they can challenge and verify the assumptions and subsequent interpretation made by the developer

Explanation / Rationale

Considering the attributes:

• Specified for walkthroughs, technical reviews, and inspections; thus, the reviews being performed cannot be informal reviews
• The purpose of evaluating quality is one of the most important objectives of a walkthrough
• This is not allowed for inspections and is typically not done in technical reviews. A moderator is needed in walkthroughs and is allowed for informal reviews
• All types of reviews can include individual preparation (even informal reviews)
• All types of reviews can produce a review report, although informal reviews do not require documentation

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

Explanation / Rationale

The average development effort is $900,000 and the average test effort is $90,000 (calculated from the four projects).
The average test-to-development effort ratio is 1:10 ($90,000 : $900,000), which means that historically, on average, the test effort is 10% of the development effort.
So if the development effort is estimated to be $800,000, the estimated test effort is estimated as:

10% * $800,000 = 0.1 * $800,000 = $80,000.

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

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

Risk assessment can use a quantitative or qualitative approach, or a mix of them. In the quantitative approach the risk level is calculated as the multiplication of risk likelihood and risk impact. So, Risk level = Risk likelihood * Risk impact
Then, Risk impact = Risk level / Risk likelihood.
In our case, Risk impact = $1,000 / 50% = $1,000 / 0.5 = $2,000.
Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

Explanation / Rationale

a) Is not correct. Risk management consists of risk analysis and risk control. Neither of these activities supports the reassembly of the files that made up the release, because these activities deal with risks, not with configuration items
b) Is not correct. Test monitoring is concerned with gathering information about testing. This information is used to assess test progress and to measure whether the test exit criteria or the test tasks associated with the exit criteria are satisfied, such as meeting the targets for coverage of product risks, requirements, or other acceptance criteria. Test control uses the information from test monitoring to provide, in the form of control directives, guidance and the necessary corrective actions to achieve the most effective and efficient testing. None of these activities deal with the management of configuration items
c) Is not correct. The whole-team approach builds on the tester’s skill to work effectively in a team context and to contribute positively to the team goals. So, it focuses on team-related issues, not on configuration items
d) Is correct. Configuration management provides a discipline for identifying, controlling, and tracking work products. Configuration management keeps a record of changed configuration items when a new baseline is created. Using configuration management, it is possible to revert to a previous baseline in order to reproduce previous test results

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. The expected result is “the application should accept the provided input and create the user”. The actual result is “The application hangs up after entering “Test input. $ä””.
b) Is not correct. There is a reference to the test case and to the related requirement and it states that the defect is rejected. Also, the defect status would not be very helpful for the developers
c) Is correct. We do not know in which test environment the anomaly was detected, and we also do not know which application (and its version) is affected
d) Is not correct. The defect report states that the anomaly is urgent, that it is a global issue (i.e., many, if not all, test administration accounts are affected) and states the impact is high for business stakeholders

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

a) Is not correct. This acceptance criterion describes what rules or regulations the system must adhere to (in this case, the right to be forgotten). This is an example of a rule-oriented acceptance criterion
b) Is correct. This acceptance criterion describes an example scenario that must be realizable by the system. This is an example of a scenario-oriented acceptance criterion
c) Is not correct. This sentence looks more like a line of code that implements some business rule. Acceptance criteria should be written in collaboration with business representatives, and therefore should be written in language they understand. This sentence will most likely be unintelligible to these stakeholders
d) Is not correct. This acceptance criterion describes what rules or regulations the system must adhere to and how compliance will be ensured. Therefore, this is an example of a rule-oriented acceptance criterion, not a scenario-based acceptance criterion

Explanation / Rationale

a) Is not correct. Although it is true that the tester can implement and execute detailed test cases based on the checklist, it does not explain how this would result in increased coverage
b) Is not correct. Checklist items should not be automated. But even if they are, the automated test scripts always execute the tests in the same way, which usually does not result in increased coverage
c) Is not correct. It is true that each checklist item should be tested separately and independently. But this impacts the test execution order and does not impact the achieved coverage, and so does not result in increased coverage
d) Is correct. If the checklists are high-level, some variability in the actual testing is likely to occur, resulting in potentially greater coverage but less repeatability. If two testers follow a checklist of high-level items, each of them may use different test data, test steps, etc. This way, one tester will probably cover some areas not covered by the other tester and this will result in increased coverage

Explanation / Rationale

Error guessing is about anticipating the errors, defects and failures based on the tester’s knowledge.
a) Is not correct. This is an example of anticipating the developer’s error
b) Is not correct. This is an example of anticipating the defect
c) Is correct. This is an example of a potential root cause of a defect, which is neither an error, defect nor failure, and difficult for the tester to anticipate
d) Is not correct. This is an example of anticipating a failure, perhaps based on experience of previous systems in this application domain

Explanation / Rationale

a) Is not correct. In exploratory testing, test cases are usually created during the exploratory testing session, alongside test analysis, test implementation and test execution
b) Is not correct. In exploratory testing, tests are simultaneously designed, executed, and evaluated while the tester learns about the test object
c) Is not correct. Exploratory testing results depend heavily on the tester’s experience, so even if the results of exploratory testing can be used as a predictor of risk and used to assess whether there will be fewer or more defects, for example, compared to the previous exploratory testing session, they are not a good example of reliable defect prediction models that can predict the number of remaining defects
d) Is correct. During exploratory testing, the testers can use any techniques that they find useful

Explanation / Rationale

a) Is not correct. Tracking test progress and identifying areas that require further attention is an example of supporting the ongoing control of testing. This is one of the purposes of test reports
b) Is not correct. Providing information on the tests executed, their results, and any issues or defects found is an example of summarizing the test activities performed at a given test level. This is one of the purposes of test reports
c) Is correct. Providing information about defects is the purpose of a defect report, not a test report
d) Is not correct. Providing information on testing planned for the next period is one of the purposes of test reports

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. The book provides general guidance, and is not a formal requirements document, a specification, or a set of use cases, user stories, or business processes
b) Is not correct. While you could consider the list as a set of test charters, it more closely resembles the list of test conditions to be checked
c) Is correct. The list of user interface best practices is the list of test conditions to be systematically checked
d) Is not correct. The tests are not focused on failures that could occur, but rather on knowledge about what is important for the user, in terms of usability

Explanation / Rationale

Let us refer to the transitions with E1, …, E5 as in the picture. The variable N denotes the number of elements currently stored. Each “Add” event increases it by 1, and each “Remove” event decreases it by 1. Notice, that when the “Add” event occurs while being in the NOT FULL state, the state changes to FULL only if N=2. If N<2, the system stays in the NOT FULL state. If N=0, no “Remove” action is possible. Similarly, if N=3, no “Add” action is possible.

Test a) can be written as E1, E3, E3, E2, E4 (so covers 4 out of 5 valid transitions, achieving 80% valid transitions coverage).
Test b) is infeasible, because after the first three “Add” actions the system is in the FULL state and there is no valid transition going from FULL triggered by the “Add” event. After the first three transitions only 60% of valid transitions coverage is achieved.
Test c) can be written as E1, E2, E4, E5, E3 (so covers 5 out of 5 valid transitions, achieving 100% valid transitions coverage).
Test d) can be written as E1, E2, E4, E5, E4 (so covers 4 out of 5 valid transitions, achieving 80% valid transitions coverage).

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