The Secretary of the Air Force is the head of which department?

• A. Department of Defense.
• B. Department of the Army.
• C. Department of Homeland Security.
• D. Department of the Air Force.

Answer: (D)

The main idea is that each military service has its own department led by a civilian secretary. The Air Force is headed by the Secretary of the Air Force, who oversees the Department of the Air Force. This department is one of the military departments under the Department of Defense, but it is not the whole defense department—that top-level leadership belongs to the Secretary of Defense. The other options point to different departments: the Army has its own Department of the Army, and Homeland Security is a separate department with its own secretary. So the correct understanding is that the Secretary of the Air Force is the head of the Department of the Air Force.