Explanation / Rationale

a) Is correct. Test-Driven Development (TDD) is a well-known example of a test-first approach to development
b) Is not correct. Coverage-Driven Development is not a correct example of a test-first approach to development
c) Is not correct. Quality-Driven Development is not a correct example of a test-first approach to development
d) Is not correct. Feature-Driven Development is not an example of a test-first approach to development, but is, instead, an agile software development methodology based around delivering features (as opposed to user stories in Scrum)

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 correct. 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. Test environment requirements are also specified, including the necessary infrastructure and tools
b) Is not correct. Test execution involves executing test cases (as part of test procedures), however it does not directly cover the other testware mentioned in the question, such as test data requirements, test environment requirements and test conditions
c) Is not correct. Test analysis is used 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. While this activity involves working with test conditions, it does not cover the other testware mentioned in the question, such as test data requirements, test environment requirements and test cases
d) Is not correct. Test implementation includes the generation of test procedures, such as manual and automated test scripts, which are created from test cases and may be assembled into test suites. Test procedures are prioritized and arranged in a test execution schedule. Test data is created, and the test environment built, and its set up verified. While this activity involves explicitly working with test cases, and may use test data requirements and test environment requirements to create test data and the test environment, it does not cover test conditions

Explanation / Rationale

a) Is not correct. Test progress reports are mostly used during test monitoring and control, and test completion, not during test design
b) Is correct. A test completion report is prepared during test completion, when a project, test level, or test type is complete and when, ideally, its exit criteria have been met. This report uses information from test progress reports and other data
c) Is not correct. Test progress reports are mostly used during test monitoring and control, and test completion, not during test analysis
d) Is not correct. Test progress reports are most used during test monitoring and control, and test completion, not during test planning

Explanation / Rationale

a) Is not correct. It is impossible to prove that there are no defects anymore in the system under test. See testing principle 1
b) Is not correct. See testing principle 7
c) Is correct. Testing finds defects and failures which reduces the level of risk and at the same time gives more confidence in the quality level of the test object
d) Is not correct. It is impossible to test all combinations of inputs (see testing principle 2)

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

a) Is not correct. Test environment readiness is a resource availability criterion; hence it belongs to the entry criteria
b) Is not correct. This is a resource availability criterion; hence it belongs to the entry criteria
c) Is correct. Estimated defect density is a measure of diligence; hence it belongs to the exit criteria.
d) Is not correct. Requirements translated into a given format result in testable requirements; hence it belongs to the entry criteria
e) Is correct. Automation of regression tests is a completion criterion; hence it belongs to the exit criteria

Explanation / Rationale

a) Is correct. 19 covers the “no discount” partition, 20 covers the “50% discount” partition, and 30 covers the “10% discount” partition. These three values cover all three of the valid equivalence partitions
b) Is not correct. 11 and 12 cover the “no discount” partition, while 20 covers the “50% discount” partition, so covering two of the three valid equivalence partitions
c) Is not correct. 1 covers the “no discount” partition, while 10 and 50 cover the “10% discount” partition. The “50% discount” partition is not covered, so overall two of the three valid equivalence partitions are covered
d) Is not correct. 29 and 31 cover the “no discount” partition, while 10 and 30 cover the “10% discount” partition. The “50% discount” partition is not covered, so overall two of the three valid equivalence partitions are covered

Explanation / Rationale

a) Is not correct. Collaborative user story writing means that all stakeholders create the user stories collaboratively, to obtain the shared vision
b) Is correct. Collaborative user story writing means that all stakeholders create the user stories collaboratively, to obtain the shared vision
c) Is not correct. Collaborative user story writing means that all stakeholders create the user stories collaboratively, to obtain the shared vision
d) Is not correct. This is the list of properties that each user story should have, not the description of the collaboration-based approach

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. Risk monitoring is part of risk control, not risk analysis
b) Is not correct. Risk identification itself does not allow us to implement risk mitigation activities. The mitigating actions are defined during the risk control phase
c) Is correct. This is an example of how risk analysis influences the thoroughness and scope of testing
d) Is not correct. Coverage items are derived using test techniques, not through risk analysis

Explanation / Rationale

a) Is not correct. Performing the impact analysis will not give information about completeness of tests. Analyzing the impact analysis of changes will help to select the right test cases for execution
b) Is not correct. Traceability does not give information about the estimated level of residual risk if the test cases are not traced back to risks
c) Is correct. Performing the impact analysis of the changes helps in selecting the test cases for the regression test
d) Is not correct. Analyzing the traceability between the test basis, test objects and test cases does not help in selecting test data to achieve the assumed coverage of the test object. Selecting test data is more related to test analysis and test implementation, not traceability

Explanation / Rationale

a) Is correct. Obtaining feedback from stakeholders early and often in the software development process can be highly beneficial. It facilitates early communication of potential quality issues, can prevent misunderstandings about requirements, and ensures that any changes in stakeholder requirements are understood and implemented sooner
b) Is not correct. The feedback is from stakeholders, and them providing feedback is unlikely to improve their understanding of their own user requirements
c) Is not correct. Obtaining feedback from stakeholders early and often in the software development process can be highly beneficial. It facilitates early communication of potential quality issues, can prevent misunderstandings about requirements, and ensures that any changes in stakeholder requirements are understood and implemented sooner. However, because changes in requirements can be understood and implemented sooner, it does not mean that unlimited changes to requirements are encouraged
d) Is not correct. The feedback is from stakeholders and does not cover communication to them. Communications to end users could include them being told about which requirements will not be implemented prior to release, but ideally this should not happen at all

Explanation / Rationale

The testware under consideration is a test charter

Test charters are the output from test design
Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct

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

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. This is a common characteristic of white-box test techniques. Test conditions, test cases, and test data are derived from a test basis that may include code, software architecture, detailed design, or any other source of information regarding the structure of the software.
b) Is not correct. This is a common characteristic of white-box test techniques. Coverage is measured based on the items tested within a selected structure and the technique applied to the test basis
c) Is correct. This is a common characteristic of experience-based test techniques. This knowledge and experience include expected use of the software, its environment, likely defects, and the distribution of those defects is used to define tests
d) Is not correct. This is a common characteristic of black-box test techniques. Test cases may be used to detect gaps within requirements and the implementation of the requirements, as well as deviations from the requirements

Explanation / Rationale

a) Is not correct. In this case one test case is still needed since there is at least one (unconditional) branch to be covered
b) Is not correct. Covering only unconditional branches does not imply covering all conditional branches
c) Is not correct. 100% branch coverage implies 100% statement coverage, not otherwise. For example, for an IF decision without the ELSE, one test is enough to achieve 100% statement coverage, but it only achieves 50% branch coverage
d) Is correct. Each decision outcome corresponds to a conditional branch, so 100% branch coverage implies 100% decision coverage

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

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

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

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

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

Given the following description of 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. The systematic identification of test conditions as coverage items often involves using test techniques both during test analysis and as part of the test design activity.
From the above description, it can be seen that test techniques are often used in the test analysis and test design activities. Boundary value analysis and equivalence partitioning are test techniques.
a) Is not correct. Test implementation is not likely to involve the use of test techniques as it is mostly concerned with assembling test cases into test procedures, while test techniques create test cases
b) Is correct. Test design is likely to involve the use of test techniques to create test cases from test conditions and coverage items
c) Is not correct. Test execution is not likely to involve the use of test techniques as it is mostly concerned with executing test procedures (and so test cases), while test techniques create test cases
d) Is not correct. Test monitoring is not likely to involve the use of test techniques. Test monitoring is mostly concerned with ongoing checks to ensure the plan is being followed, while test techniques create test cases
e) Is correct. Test analysis is likely to involve the use of test techniques to identify test conditions

Explanation / Rationale

There are three equivalence partitions: {..., 10, 11}, {12}, and {13, 14, ...}.
The boundary values are 11, 12 and 13. In the three-point boundary value analysis for each boundary, we need to test the boundary and both its neighbors, so:

• for 11 we test 10, 11, 12

• for 12 we test 11, 12, 13

• for 13 we test 12, 13, 14

Altogether we need to test 10, 11, 12, 13, and 14

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

Explanation / Rationale

a) Is not correct. Adequate time for individuals is a success factor
b) Is not correct. Splitting work products into small adequate parts is a success factor
c) Is not correct. Avoiding behaviors that might indicate boredom, exasperation, etc. is a success factor
d) Is correct. During reviews one can find defects, not failures

Explanation / Rationale

a) Is not correct. Exploratory testing uses test charters, not a list of possible defects/failures. Although exploratory testing can incorporate the use of other test techniques, in this case fault attack is the most likely option
b) Is correct. This is a list of possible failures. Fault attacks are a methodical approach to the implementation of error guessing and require the tester to create or acquire a list of possible errors, defects and failures, and to design tests that will identify defects associated with the errors, expose the defects, or cause the failures
c) Is not correct. The tester is using a checklist of items to support their testing. Both error guessing and checklist-based testing use such lists, however, the list here is of possible failures, not test conditions, and so the MOST PROBABLE test technique is fault attack, which focuses on errors, defects and failures
d) Is not correct. BVA is based on an analysis of boundary values of equivalence partitions. The above list does not mention equivalence partitions or their boundaries

Explanation / Rationale

Consider:

i. These behaviors are easily detectable while the software is running. Hence, dynamic testing shall be used to identify them
ii. This is an example of deviations from standards, which is a typical defect that is easier found with static testing
iii. If the software is executed during the test, it is dynamic testing
iv. Identifying defects as early as possible is the test objective of both static testing and dynamic testing
v. This is an example of gaps in the test basis traceability or coverage, which is a typical defect that is easier found with static testing

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

Explanation / Rationale

There are two equivalence partitions that are not yet covered, which correspond to “student discount” and “pensioner discount”.
a) Is not correct. CY – BY = 64, so these inputs correspond to the already covered “no discount” partition
b) Is correct. CY – BY = 65, so these inputs correspond to a partition that is not yet covered (“pensioner discount”)
c) Is not correct. CY – BY = –65, so these inputs correspond to the already covered “error message” partition
d) Is not correct. CY – BY = 18, so these inputs correspond to the already covered “no discount” partition
e) Is correct. CY – BY = 0, so these inputs correspond to a partition that is not yet covered (“student discount”)

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

Because TC1 and TC3 failed in Execution 1 (i.e., test (1) and test (3)), test (4) and test (6) are confirmation tests.
Because TC2 and TC3 failed in Execution 2 (i.e., tests (5) and (6)), test (8) and test (9) are also confirmation tests.
TC2 passed in Execution 1 (i.e., test (2)), so test (5) is a regression test.
TC1 passed in the Execution 2 (i.e., test (4)), so test (7) is also a regression test.
Thus:
a) Is not correct
b) Is correct
c) Is not correct
d) Is not correct

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 not correct. In agile software development, deliverables are produced in each iteration, and the frequent delivery of increments necessitates extensive regression testing. Although some (or all) of this regression testing may be automated, the regression testing (automated or not) cannot be replaced by system test automation
b) Is correct. If a sequential development model is used, then early in the lifecycle no code is available for execution, and so during this time static testing (e.g., reviews) is performed. Later in the lifecycle, when code is available for execution, dynamic testing is possible. Note, however, that preparation for dynamic testing will often occur early in any software development lifecycle
c) Is not correct. If an iterative development model, like agile software development, is used, then component tests may well be used for regression testing for each iteration. In which case, there is a strong argument for automating these component tests, which will have to be run frequently, and there is unlikely to be a strong argument for developers performing these component tests manually
d) Is not correct. In most incremental development models, deliverables are produced in each increment, requiring both static and dynamic testing at all test levels for each increment delivered

Explanation / Rationale

a) Is correct. It is important that testers are involved from the beginning of the software development lifecycle (SDLC). It will increase understanding of design decisions and will detect defects early.
b) Is not correct. Both developers and testers will have more understanding of each other's work products and how to test the code
c) Is not correct. End users will not help the testers in increasing the quality of defect reports; also, users usually do not participate in low-level testing levels like integration testing
d) Is not correct. Being certified does not automatically mean that the tester will be better in test design

Explanation / Rationale

a) Is not correct. In all types of reviews there is more than one role, even in informal ones
b) Is correct. There are several activities during the formal review process
c) Is not correct. Documentation to be reviewed should be distributed as early as possible
d) Is not correct. Defects found during the review should be reported

Explanation / Rationale

Considering each of the listed example defects:

i. Two different parts of the design specification disagree due to the complexity of the design – this is an example of a specification defect, which includes inconsistencies, ambiguities, contradictions, omissions, inaccuracies, and duplications, which can most easily be found by static testing
ii. A response time is too long and so makes users lose patience – this is an example of a response time defect, which can only be detected in practice by executing the program and measuring the response time, which can most easily be found by dynamic testing
iii. A path in the code cannot be reached during execution - this is an example of a coding defect, which includes variables with undefined values, undeclared variables, duplicated or unreachable code, and excessive code complexity, which can most easily be found by static testing
iv. A variable is declared but never subsequently used in the program - this is an example of a coding defect, which includes variables with undefined values, undeclared variables, duplicated or unreachable code, and excessive code complexity, which can most easily be found by static testing
v. The amount of memory needed by the program to generate a report is too high – this is an example of a performance defect, which can only be detected in practice by executing the program and measuring the memory used, which can most easily be found by dynamic testing

Thus:
a) Is not correct
b) Is not correct
c) Is not correct
d) Is correct. The correct match for static testing is i, iii, and iv

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

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 not correct. The paragraph contains information on test levels and exit criteria, which are part of the test approach
b) Is not correct. The paragraph contains information on test levels and exit criteria, which are part of the test approach
c) Is not correct. The paragraph contains information on test levels and exit criteria, which are part of the test approach
d) Is correct. The paragraph contains information on test levels and exit criteria, which are part of the test approach

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