(

a) Optional settlement consists of a partial distribution of the actuarial present value of the portion, as specified in this section, of the member’s unmodified monthly allowance, as prescribed in

Section 21362, 21362.2, 21363, 21363.1, 21363.4, or 21423, when a service retirement allowance is payable. The actuarial present value shall be based upon the investment return and postretirement mortality assumptions adopted by the board for that purpose. The member may elect to receive the actuarial present value of no less than percent and no more than percent of his or her unmodified allowance. The member may elect to receive the remaining portion of the unmodified allowance, not distributed as a lump-sum payment, under one of the settlements specified in this

article for the remainder of his or her lifetime and thereafter to his or her designated beneficiary, unless this amount is solely limited to the survivor continuance portion. The portion of the unmodified allowance equivalent to the survivor continuance pursuant to

Section may not be distributed as a lump-sum payment. The benefits provided under this

section may not exceed the benefits that would have otherwise been provided under any other

section in this article. (

b) This

section shall only apply to the following members who retire on or after January 1, 1999, and on or before December 31, 2017:

(1) State peace officer/firefighter members in State Bargaining Unit 6.

(2) State peace officer/firefighter members in State Bargaining Unit and state patrol members in State Bargaining Unit 5, if a memorandum of understanding has been agreed upon by the state and the recognized employee organization to become subject to this section.

(3) This

section shall also apply to state peace officer/firefighter members and state patrol members in related supervisory and confidential positions, if the Department of Human Resources has approved their inclusion.