(a) Preferred evidence. Preferred evidence that a marriage has ended is--
(1) A certified copy of the decree of divorce or annulment; or
(2) Evidence of the death (See Sec. 219.23) of a party to the marriage.
(b) Other evidence that a marriage has ended. If preferred evidence that the marriage has ended cannot be obtained, the claimant must explain the reason therefor and submit other convincing evidence that the marriage has ended. (Approved by the Office of Management and Budget under control numbers 3220-0021 and 3220-0140)