During planning, the chief audit executive submits a risk-and-control questionnaire to management of the activity...

Comprehensive and Detailed Explanation:

Risk-and-control questionnaires are structured tools used to quickly determine whether specific control activities are formally in place. They are efficient (D) because they provide management’s input on whether defined controls exist, helping auditors identify gaps before fieldwork. However, they are not the most effective way to understand processes (C) since questionnaires rely on management’s responses, which may be biased or incomplete. Instead, walkthroughs and direct observation provide more depth. Options A and B are incorrect since questionnaires are efficient and do not prevent team involvement. Therefore, the correct view is that such questionnaires are an efficient tool for confirming control existence, not for complete process understanding.