Define "black-box testing."

Black-box testing is defined as a testing approach where the tester evaluates the functionality of an application without any knowledge of its internal code structures or workings. This method focuses solely on input and output, thereby allowing testers to verify that the software behaves as expected from the user's perspective. The emphasis is on the requirements and specifications rather than the implementation.

In this context, the other options do not accurately capture the essence of black-box testing. For instance, analyzing internal workings directly contradicts the definition since black-box testing is centered around the absence of this knowledge. Additionally, while performance testing can be one aspect of black-box testing, this technique encompasses a broader range of functional testing beyond just performance measures. Lastly, requiring source code access implies a white-box testing approach, which is based on knowledge of the internal coding and architecture of the application. Thus, the correct definition effectively emphasizes the user's experience rather than the software's underlying structure.