(a) Prior to the effective date of his or her retirement, but not thereafter except upon the death of a spouse, a member may elect to receive his or her annuity as a straight life annuity payable throughout his or her life, or he or she may elect to receive the actuarial equivalent, at the time, of his or her straight life annuity in a reduced annuity payable throughout his or her life, and nominate a beneficiary, in accordance with option A or B set forth below:

Option A -- Joint and survivor annuity. -- Upon the death of a retirant who elected option A, his or her reduced annuity shall be continued throughout the life of and paid to the beneficiary, having an insurable interest in the retirant's life, whom the retirant nominated by written designation duly executed and filed with the board of trustees prior to the effective date of his or her retirement; or

Option B -- Modified joint and survivor annuity. -- Upon the death of a retirant who elected option B, one half of his or her reduced annuity shall be continued throughout the life of and paid to the beneficiary, having an insurable interest in the retirant's life, whom the retirant nominated by written designation duly executed and filed with the board of trustees prior to the effective date of his or her retirement.

(b) Upon the death of a spouse, a retirant may elect any of the retirement options offered by the provisions of this section in an amount adjusted on a fair basis to be of equal actuarial value as the annuity prospectively in effect relative to the retirant at the time the new option is elected.

(c) Upon divorce, a retirant may elect to change any of the retirement benefit options offered by the provisions of this section to a life annuity in an amount adjusted on a fair basis to be of equal actuarial value of the annuity prospectively in effect relative to the retirant at the time the option is elected: Provided, That the retirant furnishes to the board satisfactory proof of entry of a final decree of divorce or annulment: Provided, however, That the retirant certifies under penalty of perjury that no qualified domestic relations order, final decree of divorce, or other court order that would restrict the election is in effect: Provided further, That no cause of action against the board may then arise or be maintained on the basis of having permitted the retirant to name a new spouse as annuitant for any of the survivorship retirement benefit options.

(d) Upon remarriage, a retirant may name the new spouse as an annuitant for any of the retirement benefit options offered by the provisions of this section: Provided, That the retirant shall furnish to the board proof of marriage: Provided, however, That the retirant certifies under penalty of perjury that no qualified domestic relations order, final decree of divorce or other court order that would restrict the designation is in effect: Provided further, That no cause of action against the board may then arise or be maintained on the basis of having permitted the retirant to name a new spouse as annuitant for any of the survivorship retirement benefit options. The value of the new survivorship annuity shall be the actuarial equivalent of the retirant's benefit prospectively in effect at the time the new annuity is elected.