What type of testing does not require knowledge of the internal workings of a system?

The correct choice is black box testing because this type of testing evaluates the functionality of the software without any knowledge of its internal code structure or logic. Testers focus on the output generated in response to input provided, ensuring that the system behaves as expected in various scenarios. This approach helps identify functional defects and ensures that user requirements are met.

In contrast, unit testing, white box testing, and integration testing typically involve an understanding of the internal workings of the system. Unit testing is aimed at individual components or functions and requires knowledge of the code, while white box testing specifically examines the structure and logic by looking at the internal code paths. Integration testing focuses on verifying the interactions between integrated components or systems, which also necessitates some awareness of how those components work together internally. Therefore, black box testing stands out as the only approach that is completely independent of the internal technical details of the software being tested.