What defines a concrete test case?

A concrete test case is defined as one that includes specific implementation values for both input data and expected results. This specificity is crucial because it allows testers to clearly understand what data needs to be used, what operations should be performed, and what the expected outcomes are under defined conditions.

When a test case is concrete, it means that it can be executed in a real testing environment, thus providing valuable feedback on whether the functionality meets the specified requirements. The clarity surrounding input values and expected results helps ensure reproducibility, facilitates communication among team members, and enhances the overall efficiency of the testing process.

The other answer choices do not align with the definition of a concrete test case. Logical operators alone do not define the specificity necessary for a concrete test case, and a high-level scenario does not provide the granularity needed for clear test execution. Additionally, the presence of expected results is vital in defining any test case; a test case without them would not give proper guidance on what to evaluate during testing.