(a) After hearing and considering the evidence or argument, the registrar shall promptly determine the challenge and issue a decision in writing.
(b) If the registrar determines that the registration should not have been canceled, the registration continues in effect.
(c) If the registrar determines that the cancellation of the registration was proper, the registrar shall cancel the registration on the 31st day after the date the registrar's decision is issued.
(d) The registrar shall retain a copy of the decision on file with the duplicate registration certificate of the challenging voter and shall deliver a copy to the voter.