Which of the following best defines a test case?

The definition of a test case is best captured by stating that it is a set of conditions under which a tester evaluates system behavior. A test case outlines the specific inputs, execution conditions, and expected results that are necessary to validate whether the software behaves as intended in various scenarios. It acts as a guide for testers to conduct their evaluations systematically and ensures that each aspect of the functionality is tested appropriately.

A test case typically includes the test input or conditions, execution steps, and the expected outcome that should result from executing the test. This structured approach is vital for assessing the functionality, performance, and reliability of the software under test.

In contrast, the other options refer to different aspects of software testing. For instance, a record of the testing team’s activities refers to overall testing documentation rather than a specific test case. A document listing all software functionalities provides an overview of what the software is supposed to do but does not provide the specifics about how those functionalities will be tested. A log of defects found during testing represents issues identified during the testing process and does not define what a test case itself is. Thus, the most accurate representation of a test case is indeed the set of conditions under which a tester evaluates system behavior.