Which of the following diagrams best represents the relationship between Examination, Questions, and Practice?

Let's analyze the core components:
1. Questions are part of both Examinations and Practice.
2. However, an Examination is a formal assessment, whereas Practice is a separate learning process. They do not overlap directly.
3. Therefore, the "Questions" circle intersects both the "Examination" circle and the "Practice" circle, while Examination and Practice remain distinct from each other.

This corresponds to the structure described in Option C.