(a) Pension benefits payable from the retirement plan and trust are:
(1) retirement annuities payable on service retirements;
(2) retirement annuities payable on disability retirements;
(3) survivor annuities payable on the deaths of members; and
(4) refunds of accumulated contributions.
(b) Nonpension group term life coverage may be provided by an electing subdivision for its employees and retirees under the optional group term life program. The board of trustees shall administer the program, and insurance proceeds are payable from the optional group term life fund.