(a) A contributing member of the Employees Retirement System of Texas who retires is entitled to a lump-sum payment, from funds of the agency or department from which the member retires, for the member's accrued vacation time as of the date of retirement, unless the member opts to receive for that accrued vacation time service credit under Section 813.511(a).
(b) A payment required by this section is payable on the date of retirement.