In Class 1-D-E shall be placed any registrant who:
    
    
        
        (a) 
         Is a student enrolled in an officer procurement program at a military college the curriculum of which is approved by the Secretary of Defense; or
     
    
        
        (b) 
         Has been enlisted in the Delayed Entry Program (DEP) at least ten days prior to his scheduled induction date; or
     
    
        
        (c) 
         Has been transferred to a reserve component of the Army, Navy, Air Force, Marine Corps or Coast Guard after a period of extended active duty, which was not for training only.