The correct answer is C) set procedures and standards for the military.
The purpose of the Department of Defense is to set procedures and standards for the military.
In the United States, the President is the Commander in Chief of the Armed Forces. As part of his cabinet, the Department of Defense is the one that leads and operates the decions to protect the country. Basically, the Department of Defense of the United States includes the Army, the Navy, the Air Force, and the Marine Corps. The Department of Defense has its headquarters in the building called "The Pentagon," in Washington D.C.