32 C.F.R. § 1633.6
Claims of a registrant will be considered in inverse order of the listing of the classes below. When grounds are established to place a registrant in one or more of the classes listed in the following table, the registrant shall be classified in the lowest class for which he is determined to be eligible, with Class 1-A-O considered the highest class and Class 1-H considered the lowest class, according to the following table:
Class 1-A-O: Conscientious Objector Available for Noncombatant Military Service Only.
Class 1-O: Conscientious Objector to all Military Service.
Class 1-O-S: Conscientious Objector to all Military Service (Separated).
Class 2-D: Registrant Deferred Because of Study Preparing for the Ministry.
Class 3-A: Registrant Deferred Because of Hardship to Dependents.
Class 3-A-S: Registrant Deferred Because of Hardship to Dependents (Separated).
Class 4-D: Minister of Religion.
Class 1-D-D: Deferment for Certain Members of a Reserve Component or Student Taking Military Training.
Class 4-B: Official Deferred by Law.
Class 4-C: Alien or Dual National.
Class 4-G: Registrant Exempted From Service Because of the Death of his Parent or Sibling While Serving in the Armed Forces or Whose Parent or Sibling is in a Captured or Missing in Action Status.
Class 4-A: Registrant Who Has Completed Military Service.
Class 4-A-A: Registrant Who Has Performed Military Service For a Foreign Nation.
Class 4-W: Registrant Who Has Completed Alternative Service in Lieu of Induction.
Class 1-D-E: Exemption of Certain Members of a Reserve Component or Student Taking Military Training.
Class 1-C: Member of the Armed Forces of the United States, the National Oceanic and Atmospheric Administration, or the Public Health Service.
Class 1-W: Conscientious Objector Ordered to Perform Alternative Service in Lieu of Induction.
Class 4-T: Treaty Alien.
Class 4-F-: Registrant Not Acceptable for Military Service.
Class 1-H: Registrant Not Subject to Processing for Induction.
32 C.F.R. §1633.6