(a) A member may elect one of the following optional forms for retirement income by filing with the Retirement Commission a written election on a form provided by the commission. A member who has been married at least one year shall be presumed to have elected the option provided in subdivision (1) of this subsection unless a contrary election is made by the member. All other members will be presumed to elect the option provided in subdivision (4) of this subsection unless a contrary election is made by the member. Any election or change of election must be filed before retirement income payments begin. No option shall be effective until a member has retired, and in the event a member dies prior to the effective date of commencement of benefits, any election of an option shall be deemed cancelled except as provided in subsection (c) of § 5-165a. The amount of income that will be paid under the options will be determined by multiplying the retirement income otherwise applicable by the actuarially equivalent option factors last adopted by the Retirement Commission. Beginning with October 1, 1982, but only with regard to benefits payable on behalf of members whose benefits have not yet commenced, such factors shall not differentiate by sex of the member, or the member’s spouse or contingent annuitant. The initial factors shall employ the interest rate and mortality table assumptions utilized for the December 31, 1980, valuation, with the factors assuming sixty per cent male and forty per cent female for members, and sixty per cent female and forty per cent male for spouses and contingent annuitants. The cost-of-living adjustment under § 5-162d shall be assumed to be three per cent. The factors shall not take into account the cost of providing the surviving spouse benefit under § 5-165a. The factors may be periodically adjusted upward or downward by the Retirement Commission to reflect changing interest, mortality or election of option patterns provided that they shall be reviewed and adjusted by January 1, 1985. Any such changes shall apply only to members whose benefits commence after the effective date of adoption of such factors. The retirement income options are as follows:

(1) A reduced amount payable to the member for his lifetime, with the provision that after his death his spouse, if surviving, shall be entitled to receive a lifetime income equal to fifty per cent of the reduced monthly amount payable to the member;

(2) A reduced amount payable to the member for his lifetime, with the provision that after his death, his contingent annuitant shall be entitled to receive a lifetime income equal to either fifty or one hundred per cent of the reduced amount payable to the member;

(3) A reduced amount payable to the member for his lifetime, with the provision that if he shall die within either a ten or twenty-year period following the date his retirement income commences, whichever is selected by the member, the reduced amount continues to his contingent annuitant for the balance of the ten or twenty-year period; or

(4) An amount payable to the member for his lifetime, with no payments continuing after the member’s death, except for a lump sum death benefit as provided in subsection (b) of § 5-168.

(b) Notwithstanding the provisions of subsection (a) of this section, a temporary minimum shall apply whenever the Retirement Commission adopts revised factors which could result in a smaller benefit to a member than would have been payable under the previously existing factors. Such minimum shall be determined as follows: (1) The benefit the member had earned as of the date of the change in factors shall be calculated, based on his final earnings and service as of that date; (2) any early retirement reduction in such benefit shall be based upon his age, as determined on the date benefits will commence, and his type of retirement; and (3) the option factor shall be determined utilizing the factors in effect prior to such change, but based on appropriate ages as of the date benefits will commence. If such minimum results in a larger benefit, the larger benefit shall be payable.