(a) Except as provided by Subsection (b), a surviving spouse who is the designated beneficiary of a retiree who did not perform a year of service after November 23, 1956, that was credited in the retirement system and who died before August 23, 1963, while receiving a retirement benefit, is eligible to receive an applicable survivor benefit available under Section 824.404.
(b) A surviving spouse who qualifies under this section for a survivor benefit is not eligible to receive a lump-sum benefit under Section 824.404(a).
(c) A benefit under this section is payable beginning on the last day of the month in which an eligible person applies for the benefit on a form prescribed by and filed with the retirement system.