(a) Who is preparing for the ministry under the direction of a recognized church or religious organization; and

(b) Who is satisfactorily pursuing a full-time course of instruction required for entrance into a recognized theological or divinity school in which he has been pre-enrolled; or

(c) Who is satisfactorily pursuing a full-time course of instruction in or at the direction of a recognized theological or divinity school; or

(d) Who having completed theological or divinity school is a student in a full-time graduate program or is a full-time intern. The registrant's studies must be related to and lead to entry into service as a regular or duly ordained minister of religion, and satisfactory progress in these studies as required by the school in which the registrant is enrolled must be maintained for continued eligibility for the deferment.