Why is pre-specifying primary outcomes helpful in studies with multiple comparisons?

Why is pre-specifying primary outcomes helpful in studies with multiple comparisons?

• A. It eliminates the need for preregistration.
• B. It guarantees a large effect will be found.
• C. It prevents all bias in data collection.
• D. It helps control the overall type I error by focusing on predefined primary outcomes and reducing the number of tests.

Answer: (D)