Notwithstanding any election under subsection (b) of
section 8434 of this title, the method described in subsection (a)(2)(B) of such section (or, if more than one form of such method is available, the form which the Board determines to be the one which provides for a surviving spouse a survivor annuity most closely approximating the annuity of a surviving spouse under
section 8442 of this title) shall be deemed the applicable method under such subsection (b) in the case of an employee, Member, former employee, or former Member who is married on the date on which an annuity contract is purchased to provide for the employee’s, Member’s, former employee’s, or former Member’s annuity under this subchapter.