(a)     Each member or retiree may, on a form provided for that purpose, signed and filed with the board, designate a beneficiary (or beneficiaries) to receive the benefit, if any, which may be payable in the event of his death. Each designation may be revoked or changed by such member or retiree by signing and filing with the board a new designation-of-beneficiary form. Upon such change, the rights of all previously designated beneficiaries to receive benefits under the system shall cease.

(b)     If a deceased member or retiree failed to name a beneficiary in the manner prescribed in paragraph (a), or if the beneficiary (or beneficiaries) named by a deceased member or retiree predeceased the member or retiree, the death benefit, if any, which may be payable under the system with respect to such deceased member or retiree, shall be paid to the estate of the member or retiree and the board, in its discretion, may direct that the commuted value of the remaining monthly income benefits be paid in a lump sum.

(c)     Any payment made to any person pursuant to this section shall operate as a complete discharge of all obligations under the system with regard to the deceased member and any other persons with rights under the system and shall not be subject to review by anyone but shall be final, binding and conclusive on all persons ever interested hereunder.