Final answer:
The primary civilian leaders within the DOD are the Secretary of Defense and the President of the United States. The Commandant of the Marine Corps is not a civilian leader.
Step-by-step explanation:
The primary civilian leaders within the DOD (Department of Defense) include:
b) The Secretary of Defense: The Secretary of Defense is the head of the entire Department of Defense and is a nonmilitary civilian.
c) The President of the United States: The President is the Commander in Chief of the Army and Navy of the United States and has the power to require the opinion of the principal officers in the executive departments.
d) The Commandant of the Marine Corps: The Commandant of the Marine Corps is not a civilian leader but is the senior-ranking officer in the Marine Corps.
Note: The Chairman of the Joint Chiefs of Staff is the top uniformed military officer, not a civilian leader within the DOD.