In order to prove marital cohabitation within the meaning of that term as used in section 602(a) or section 312(c)1 of the Act, as amended, claimant shall be required to establish:

(a) A valid marriage, such marriage to be shown by the best evidence obtainable in accordance with the provisions of regulations of the Department of Veterans Affairs.

(b) The fact of living together as man and wife, with such fact to be established by:

(1) Statement of the widow or widower showing that he or she and the veteran lived together as man and wife and also showing the place or places of residence during such marital cohabitation and the approximate time of such residence; or

(2) Statement of two competent persons showing that they personally knew the claimant and veteran and that they had personal knowledge that said claimant and veteran lived together as man and wife and were recognized as such.

(c) The fact that the marital status existed at the time of the death of the veteran or where it is established that the veteran is deceased, as provided in section 312(a)1 of the Act, as amended, at the beginning of such 7-year period, such fact to be established by:

(1) Statement by claimant that he or she and the veteran had not been divorced and that there had been no annulment of the marriage.

(2) Statement of claimant that he or she was not remarried at the time of making application.

(3) Statement of two competent persons showing that they personally knew the claimant and the veteran; that they personally knew of the marriage relationship between claimant and veteran; that to the best of their knowledge and belief there had been no divorce and no annulment of the marriage and that claimant was not remarried at the time of making and filing application.