Sec. 15. A participant whose employment in a position described in section 8 of this chapter is terminated is entitled to a retirement benefit computed under section 16 or 18 of this chapter, beginning on the date specified by the participant in a written application, if all of the following conditions are met:
(1) The application for retirement benefits and the choice of the retirement date is filed on a form provided by the board, and the retirement date is:
(A) after the cessation of the participant's service;
(B) on the first day of a month; and
(C) not more than six (6) months before the date the application is received by the board.
However, if the board determines that a participant is incompetent to file for benefits and choose a retirement date, the retirement date may be any date that is the first of the month after the time the participant became incompetent.
(2) The participant:
(A) is at least sixty-two (62) years of age and has at least eight (8) years of service credit;
(B) is at least fifty-five (55) years of age and the participant's age in years plus the participant's years of service is at least eighty-five (85); or
(C) has become permanently disabled.
(3) The participant is not receiving and is not entitled to receive any salary for services currently performed, except for services rendered as a senior prosecuting attorney under IC 33-39-10-1.