Which components are included in the Department of Defense?

• A. The Central Intelligence Agency.
• B. The Department of Homeland Security.
• C. Office of the Secretary of Defense; Joint Chiefs of Staff; Joint Staff; and the Departments of the Army, Navy (including the Marine Corps), and Air Force (including Space Force).
• D. The Department of State.

Answer: (C)

DoD is organized around its central leadership and the military services it oversees. The components include the Office of the Secretary of Defense, the Joint Chiefs of Staff, the Joint Staff, and the three military departments: Army; Navy (which includes the Marine Corps); and Air Force (which includes the Space Force). The Marine Corps is actually part of the Navy, and Space Force is under the Air Force, reflecting how the services are structured within DoD. The other options aren’t part of DoD: the Central Intelligence Agency is part of the Intelligence Community, the Department of Homeland Security is a separate cabinet department, and the Department of State handles diplomacy.