Any member of fund B separated from the service of the municipality by which the member is employed, except for cause, after completing at least five years of continuous service but before reaching the voluntary retirement age, shall be entitled to a retirement allowance upon reaching the voluntary retirement age; provided, at the option of the member, the retirement allowance may commence on the date of such separation and be payable in such an amount as may be determined by the Retirement Commission to be the actuarial equivalent of the retirement allowance that would have been payable except for the election of such option.