S.C. Code Ann. § 9-9-80

All retirement allowances are payable in monthly installments. Upon the death of a retired member, the retirement allowance for the month the retired member died, if not previously paid, must be paid to the member's designated beneficiary, if the beneficiary is living at the time of the member's death, otherwise to the estate of the member. If the retired member elected a survivor option pursuant to the optional forms of allowances in Section 9-9-70, any allowance payable to a survivor beneficiary commences in the month after the death of the retired member.