Section 77A. Any employee in the employ of a city or town, who is eligible for superannuation retirement under the provisions of section seventy-seven in effect in the city or town in which he is employed shall have the right at the time of retirement to elect one of the following options for the payment of his pension:—

Option A. The full yearly amount of pension payable to such employee on the date of his retirement.

Option B. A lesser amount of yearly pension which shall be payable to such employee during his lifetime, with a provision that one half of the yearly amount of such lesser pension shall be continued during the lifetime of and paid to his widow who was his spouse at time of his retirement; provided, however, that the surviving spouse shall receive not less than one half of the pension such employee is receiving at the time of his death. The yearly amount of such lesser pension shall be determined so that the value, on the date the retirement and pension becomes effective, of the prospective payments to such employee and to such widow shall be the actuarial equivalent of the value on such date of the full pension specified in option A of this section.

If a laborer, as defined in section seventy-seven, has served continuously for not less than twenty years in such city or town and dies before being retired, his widow shall receive the same yearly amount which she would have received had he been in the employ of such city or town for twenty-five years, had his retirement taken place on the date of his death and had he elected to be retired under the provisions of option B. Said yearly amount shall be paid to such widow so long as she remains unmarried; provided, that she has been married to such employee not less than ten years prior to his death, and that they were living together at the time of his death or living apart for justifiable cause other than desertion or moral turpitude on the part of the wife. The computation of the actuarial equivalent of the pension payable to any such employee and the widow under the provisions of this option shall be subject to supervision and verification by an actuary appointed by the public employee retirement administration commission and the expenses for such service shall be paid by the city or town in which such employee was employed. The provisions of this section shall become effective in a city having Plan D or Plan E charter by the affirmative vote of two thirds of all members of the city council, and in the case of any other city by vote of the city council subject to the provisions of its charter, and in a town by a majority vote at an annual town meeting.