(a) the month in which the beneficiary(1) reached 65 years of age, having become retired from regular employment,
(2) having reached 65 years of age, became retired from regular employment, or
(3) reached 70 years of age;
(b) the month following the month in which the application was received, but if the beneficiary had reached 70 years of age before the month in which the application was received, then the later of(1) the twelfth month preceding such following month, or
(2) the month in which the beneficiary reached 70 years of age;