(a) A person terminates participation in the optional retirement program, without losing any accrued benefits, by:
(1) death;
(2) retirement; or
(3) termination of employment in all institutions of higher education.
(b) A change of company providing optional retirement program benefits or a participant's transfer between institutions of higher education is not a termination of employment.
(c) The benefits of an annuity purchased under the optional retirement program are available only if the participant obtains the age of 70-1/2 years or terminates participation in the program as provided by Subsection (a).