How is an Option D benefit calculated if a member dies before his/her 55th birthday?

The designated beneficiary is entitled to receive the Option C allowance the member would have been entitled to receive if the member had attained age 55 and retired on the date he /she died. The number of years of service that the member had been granted when he/she died plus any service for which the beneficiary makes a “make-up” payment will be used in the calculation.