(a) Any district attorney, former district attorney or former circuit solicitor of this state:
may elect to become supernumerary district attorney of the state by filing a written declaration to that effect with the Governor.
(b) Any district attorney, former district attorney or former circuit solicitor who has served in that office as district attorney for not less than 24 years, or for not less than six terms, the last 10 years of such service having been continuous, may elect to become a supernumerary district attorney of the state by filing a written declaration to that effect with the Governor at any time not more than 90 days prior to the end of the 24-year period.
(c) This section shall apply only to district attorneys, former district attorneys or former circuit solicitors who have been elected to that office.