If a group C member in receipt of a retirement allowance dies, his or her dependent spouse shall receive until her or his death a retirement allowance which shall be equal to 70 percent of the retirement allowance to which the member was then entitled, without optional modification, irrespective of whether such member had elected an option hereunder. (Added 1971, No. 231 (Adj. Sess.), § 4; amended 1985, No. 160 (Adj. Sess.), § 3.)