(

a) If upon receipt of proof of death of a retired member who was receiving an unmodified allowance and who retired under this part after June 30, 1972, there is a remaining balance of the member’s accumulated retirement contributions, the balance shall be paid to the member’s beneficiary. (

b) Upon receipt of proof of death of a retired member’s option beneficiary after the beneficiary begins to receive an allowance, the remaining balance of a member’s accumulated retirement contributions, if any, shall be paid to the beneficiary designated by the option beneficiary to receive that payment. (

c) The remaining balance of a retired member’s accumulated retirement contributions shall be the difference between the balance of the accumulated retirement contributions on the effective date of the member’s retirement and the total retirement allowance paid or payable to the retired member on the date of the member’s death.

If the retired member predeceased the option beneficiary, the remaining balance of the retired member’s accumulated retirement contributions shall be the difference between the balance of the accumulated retirement contributions on the effective date of the member’s retirement and the total retirement allowance paid or payable to the retired member and the option beneficiary on the date of the option beneficiary’s death. (

d) Payments pursuant to this

section shall include interest on the remaining balance of accumulated retirement contributions calculated from the date the last allowance payment was made to the date the remaining balance of accumulated retirement contributions is paid. (

e) A designated beneficiary may waive the right to the death payment in accordance with the requirements established by the system. The waiver shall be submitted on a properly executed form prescribed by the system. The filing of a waiver by a beneficiary constitutes a complete and immediate discharge of all obligations of the board, the system, or the plan to or on behalf of the beneficiary.