In Class 1-D-D shall be placed any registrant who:

(a)(1) Has been selected for enrollment or continuance in the Senior (entire college level) Army Reserve Officer's Training Corps, or the Air Force Reserve Officer's Training Corps, or the Naval Reserve Officer's Training Corps, or the Naval and Marine Corps officer candidate program of the Navy, or the platoon leader's class of the Marine Corps, or the officer procurement programs of the Coast Guard and the Coast Guard Reserve, or is appointed an ensign, U.S. Naval Reserve while undergoing professional training; and

(2) Has agreed in writing to accept a commission, if tendered, and to serve subject to order of the Secretary of the military department having jurisdiction over him (or the Secretary of Transportation with respect to the U.S. Coast Guard), not less than 2 years on active duty after receipt of a commission; and

(3) Has agreed to remain a member of a regular or reserve component until the eighth anniversary of his receipt of a commission. Such registrant shall remain eligible for Class 1-D-D until completion or termination of the course of instruction and so long thereafter as he continues in a reserve status upon being commissioned except during any period he is eligible for Class 1-C under the provision of § 1630.12; or

(b) Is a fully qualified and accepted aviation cadet applicant of the Army, Navy, or Air Force, who has signed an agreement of service and is within such numbers as have been designated by the Secretary of Defense. Such registrant shall be retained in Class 1-D-D during the period covered by such agreement but in no case in excess of four months; or

(c) Is other than a registrant referred to in paragraph (a) or (d) of this section who:

(1) Prior to the issuance of orders for him to report for induction; or

(2) Prior to the date scheduled for his induction and pursuant to a proclamation by the Governor of a State to the effect that the authorized strength of any unit of the National Guard of that State cannot be maintained by the enlistment or appointment of persons who have not been issued orders to report for induction; or

(3) Prior to the date scheduled for his induction and pursuant to a determination by the President that the strength of the Ready Reserve of the Army Reserve, Naval Reserve, Marine Corps Reserve, Air Force Reserve, or Coast Guard Reserve cannot be maintained by the enlistment or appointment of persons who have not been issued orders to report for induction:

(d) At any time has enlisted in the Army Reserve, the Naval Reserve, the Marine Corps Reserve, the Air Force Reserve, or the Coast Guard Reserve and who thereafter has been commissioned therein upon graduation from an Officer's Candidate School of such Armed Force and has not has been ordered to active duty as a commissioned officer. Such registrant shall remain eligible for Class 1-D-D so long as he performs satisfactory service as a commissioned officer in an appropriate unit of the Ready Reserve, as determined under regulations prescribed by the Secretary of the department concerned; or

(e) Is serving satisfactorily as a member of a reserve component of the Armed Forces and is not eligible for Class 1-D-D under the provisions of any other paragraph of this section: Provided: That, for the purpose of this paragraph, a member of a reserve component who is in the Standby Reserve or the Retired Reserve shall be deemed to be serving satisfactorily unless the Armed Forces of which he is a member informs the Selective Service System that he is not serving satisfactorily.