(a) The commissioner shall establish and maintain a pool of candidates for the various classes of positions as the commissioner deems necessary or desirable to meet the needs of the service.
(b) At the time a pool of candidates is established, the commissioner shall determine the period during which such pool shall remain in force.
(c) No person who is required to register for the federal draft under 50 U.S.C. Appx. § 453 shall be eligible for employment with the state of Tennessee until such person has registered for such draft.