A claimant will be considered to have the relationship of stepchild of an employee, and will be considered a child for annuity but not for lump-sum benefit purposes if -
(a) The claimant's natural or adoptive parent married the employee after the claimant's birth; and
(b) The marriage between the employee and the claimant's parent is a valid marriage under applicable State law (see §§ 222.12 and 222.13), or would be valid except for a legal impediment; and
(c) The employee and the claimant's parent were married at least one year before the date -
(1) On which the spouse applies for an annuity based on having the employee's child in care; or
(2) On which the employee's annuity can be increased under the social security overall minimum provision; or
(d) The employee and the claimant's parent were married at least nine months before the date on which the employee died if the claimant is applying for a child's annuity; or if the employee and the claimant's parent were married less than nine months, the employee was reasonably expected to live for nine months, and -
(1) The employee's death was accidental; or
(2) The employee died in the line of duty as a member of the armed forces of the United States; or
(3) The widow(er) was previously married to the employee for at least nine months.