Should a contributor be discontinued from service not voluntarily, or an elected city officer complete his term of office and discontinue service after having completed ten years of total service or voluntarily after having completed twenty-five years of total service but before reaching superannuation retirement age, he shall be paid as he may elect, as follows: (1) the full amount of the accumulated deduction standing to his credit in the members' annuity reserve account; or (2) a member's annuity of equivalent actuarial value to his accumulated deductions standing to his credit in the member's annuity reserve account and, in addition, a city annuity having a value equal to the present value of a city annuity beginning at superannuation retirement age, but based on the period of service up to the date of discontinuance from service and not on the period of service required to reach superannuation retirement age. The same options shall be available to beneficiaries in case of involuntary retirement as provided herein in the case of superannuation retirement.