A commissioner entitled to a retirement benefit may elect, subject to written notice of his election filed prior to retirement with the state treasurer and duly acknowledged by him to have a benefit payable under one of the options hereinafter set forth in lieu of all other benefits he is otherwise entitled to receive, and shall file a written designation of a contingent annuitant to receive benefits under an option to be payable after his death. The optional benefits payable shall be in accordance with the terms of the election of option last received and acknowledged by the state treasurer and the contingent annuitant entitled to benefits under said option shall be the person in the written designation of contingent annuitant last received by the state treasurer prior to the retirement of the commissioner. The amount of any optional benefit shall be based on option rates adopted from time to time by the state treasurer and shall be actuarially equivalent in value to the benefit that would otherwise be payable, except that an option commencing after age sixty-five (65) shall not be less than if based on an option rate that would have been applicable had retirement occurred at age sixty-five (65). The election of an option shall be null and void if the contingent annuitant dies before benefits commence. If a commissioner has duly designated a contingent annuitant and is eligible to retire at the time of his death a benefit will be payable to the contingent annuitant as though the commissioner had retired the day before his death. If a commissioner has not duly designated a contingent annuitant and is eligible at the time of his death to have retired under the public service commissioners' retirement system provided by §§ 65-151 — 65-168, the benefit will be an amount payable monthly to his widow, if she is then living, for the remainder of her unremarried life, determined in the same way as an option 1 (joint and survivor) benefit, or the benefit may be a refund of his contributions to the public service commissioners' retirement system (including any contributions made by such commissioner to any other state retirement system and subsequently transferred to the public service commissioners' retirement system in the manner prescribed by §§ 65-151 — 65-168) if the widow so elects.

Option 1. The joint and survivor benefit shall be payable for the life of the retired commissioner and thereafter to the contingent annuitant for life.

Option 2. The modified joint and survivor benefit shall be payable for the life of the retired commissioner and thereafter one half (½) of such amount shall be payable to the contingent annuitant for life.