What distinguishes black box testing from white box testing in the context of RSI Phase 5?

The distinction between black box testing and white box testing is fundamentally based on their approaches to testing software. Black box testing emphasizes evaluating the functionality of an application based solely on its inputs and expected outputs, without any knowledge of the internal workings or the code that generates those outputs. This method allows testers to validate whether the software behaves as intended from an end-user perspective, ensuring that it meets specified requirements.

In contrast, white box testing delves into the internal structure of the software. It requires an understanding of the code, algorithms, and logic that govern the application's operation. This type of testing often involves inspecting the code for errors and verifying that the implementation aligns with the software's design.

Thus, the correct answer highlights the core difference whereby black box testing focuses on the external behavior of software while white box testing scrutinizes its internal mechanisms, making it essential for understanding how both approaches contribute to software quality assurance.