(a) The provisions of this Code section shall apply only to persons who become members of this retirement system on or after July 1, 2012.

(b) A member may make a one-time election to convert the retirement allowance otherwise payable to him or her into a modified retirement allowance of equivalent actuarial value and designate a natural person to receive a survivors benefit in accordance with one of the options set forth in paragraphs (1), (2), (3), or (4) of this subsection. Such retirement allowance shall be actuarially reduced in accordance to the designated survivor's projected life span. Such actuarial adjustment shall be computed upon the basis of the mortality tables and rates of interest last adopted by the board of trustees. Such election may be made only after the member has become eligible to retire and before the first payment of his or her retirement allowance normally becomes due. Such election shall be irrevocable except as otherwise provided in this Code section.

(1) Option one, known as the 100 percent joint and survivor option, shall consist of a reduced retirement allowance which is payable during the life of the retired member and which, upon his or her death, shall be continued at the same rate throughout the life of and paid to the designated survivor.

(2) Option two, known as the 66 2/3 percent joint and survivor option, shall consist of a reduced retirement allowance which is payable during the life of the retired member and which, upon his or her death, shall be continued at the rate of two-thirds the reduced retirement allowance throughout the life of and paid to the designated survivor.

(3) Option three, known as the 50 percent joint and survivor option, shall consist of a reduced retirement allowance which is payable during the life of the retired member and which, upon his or her death, shall be continued at the rate of one-half the reduced retirement allowance throughout the life of and paid to the designated survivor.

(4) Option four, known as the pop-up option, shall be the election of options one, two, or three, with the added provision that in the event the designated survivor predeceases the retired member, the retirement allowance payable to the retired member after the death of the designated survivor shall be equal to the maximum retirement allowance which the retired member would have been entitled to receive under this chapter had such election not been made.

(c) In the event a member is not married at the time he or she retires and the retired member does not elect a survivor's option and such member subsequently marries, the retired member may elect to begin receiving an actuarially reduced benefit of equivalent value and establish on behalf of the newly acquired spouse an option under this Code section. Such election shall be made within six months after the marriage.

(d) In the event a retired member makes an election under subsection (b) of this Code section on behalf of a spouse and such spouse predeceases the retired member and the retired member subsequently remarries, the retired member may elect to begin receiving an actuarially reduced benefit of equivalent value and establish on behalf of a new designated survivor pursuant to an option under this Code section.

(e) In the event a retired member makes an election under subsection (b) of this Code section on behalf of a spouse and a final judgment of complete divorce from the spouse is entered, then:

(1) The retired member may elect to continue the optional allowance with the former spouse designated to receive all amounts and benefits upon the death of the retired member; or

(2) The retired member may revoke the appointment of such spouse as a beneficiary; provided, however, that in such event the retirement benefit received by the retired member shall not increase. Such revocation may be made at any time after the entry of the final judgment of divorce. If the retired member elects to revoke the election, the spouse shall be treated in the same manner as if he or she had predeceased the retired member under subsection (d) of this Code section.

(f) If an active vested member of this retirement system dies and is survived by a legal spouse, such spouse shall receive a benefit as if the member has retired on the date of his or her death and had elected option three.