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.