Section 13-559. Termination of options

Where a contributor has elected an
  option in accordance with section 13-558 of this chapter and where  such
  option  provides that upon the death of the contributor after retirement
  a guaranteed lump sum payment in a  stated  dollar  amount,  or  that  a
  guaranteed  lump  sum  payment  of a specific number of variable annuity
  units equal to a stated dollar amount, or that  a  guaranteed  lump  sum
  payment  of a specific number of variable annuity units shall be payable
  to a designated  beneficiary,  and  where  such  designated  beneficiary
  predeceases  the  retired  contributor, then the retired contributor may
  file a fully certified request, upon a form provided by such board, that
  his or her optional election terminate. Upon such  request,  accompanied
  by  evidence  of the death of the designated beneficiary, the previously
  elected option shall be null and  void,  and  the  retirement  allowance
  thereafter  payable  to  such  retired contributor shall be such greater
  amount that the actuary shall  compute  to  be  the  equivalent  of  the
  benefits payable had no such option been filed.