What is a test case in software testing?

• A. A single input used to run the program
• B. A plan for deploying software
• C. A defined set of inputs and the expected outputs for them
• D. A tool for debugging

Answer: (C)

A test case is a defined set of inputs along with the outputs you expect to see. This pairing lets you check that a specific part of the software behaves correctly by comparing what the program actually does with what you predicted it should do. It’s more than just providing inputs; it includes the expected results so you know when the feature works (or where it fails). Test cases are usually run in a controlled way, and you can repeat them to ensure changes don’t break existing behavior. When you gather several test cases, you get a test suite that checks different scenarios and edge conditions. The other descriptions don’t capture this exact idea: a single input doesn't specify the expected outcome, a deployment plan is about delivering software, and a debugging tool helps find problems rather than define expected behavior.