This part applies to the following:

(a) Active U.S. Armed Forces personnel of the Army, Air Force, Navy, and Marine Corps, and the Coast Guard wherever they are stationed.

(b) U.S. Armed Forces Reserve personnel only when they are performing Federal duties or engaging in activities directly related to performing a Federal duty or function.

(c) National Guard personnel only when called or ordered to active duty in a Federal status within the meaning of Title 10, United States Code.