The correct option is "commander in chief"
United States Armed Forces are formed by: the Navy, the Marine Corps, the Coast Guard, the Air Force and the Army. All the forces are part of the uniformed services of the United States and are under the civilian control of the President of the United States, who acts as Commander-in-Chief. All services except the Coast Guard, which are under the supervision of the Department of Homeland Security, depend on the Department of Defense, which is headed by the Secretary of Defense who must also be a civilian.