Any person who became a member on or before April 25, 1973 and who qualifies for a retirement allowance shall, at time of retirement, make an irrevocable election to receive either the retirement allowance by RCW
41.32.498 as now or hereafter amended or to receive a retirement allowance pursuant to this section consisting of: (1) An annuity which shall be the actuarial equivalent of his or her accumulated contributions at his or her age of retirement, (2) A basic service pension of one hundred dollars per annum, and (3) A service pension which shall be equal to one one-hundredth of his or her average earnable compensation for his or her two highest compensated consecutive years of service times the total years of creditable service established with the retirement system: PROVIDED, That no beneficiary now receiving benefits or who receives benefits in the future, except those beneficiaries receiving reduced benefits pursuant to RCW
41.32.520(1)(a) or
41.32.530, shall receive a pension of less than six dollars and fifty cents per month for each year of creditable service established with the retirement system. Pension benefits payable under the provisions of this section shall be prorated on a monthly basis and paid at the end of each month.