(1) Any member in Group 1 shall be eligible for a retirement benefit upon completion of twenty-five (25) years of creditable service.
(2) If the member is less than fifty-five (55) years of age, such benefit shall be the actuarial equivalent of the retirement benefit which would be payable to the member at fifty-five (55) years of age.
(3) This section shall be optional for political subdivisions participating under chapter 35 of this title.