(

a) Notwithstanding Sections and 31760, optional settlement consists of a retired member’s right to elect in writing to have his or her retirement allowance reduced and to designate his or her spouse who is not otherwise eligible to receive a survivor allowance. The survivor allowance shall be determined on an actuarial basis by the reduction in the member’s allowance and may not, in the opinion of the board and the actuary, place any additional financial burden on the retirement system. (

b) A member who elected to receive an optional settlement under

Section 31762, 31763, or 31764, involving a life contingency of a beneficiary, may elect optional settlement if the beneficiary predeceases the member or, if a former spouse was named, in the event of a dissolution or annulment of the marriage or a legal separation in which the judgment dividing the community property awards the total interest in the retirement system to the retired member. (

c) A member who married at least months prior to the date this

section becomes operative may file an election with the board of retirement within days after the operative date. The election shall become effective the first day of the month following receipt of the election by the board. A member who fails to elect within that 60-day period shall retain the right to make an election under this

section subject to the waiting period provided in subdivision (d). (

d) Except as provided in subdivision (c), the election under this

section shall become effective months after the date it is filed with the board, provided that neither the member nor his or her spouse dies prior to the effective date of the election. (

e) An election under this

section is irrevocable. (

f) This

section may not become operative until the board of supervisors elects, by resolution adopted by a majority vote, to make this

section operative in the county.