(a) The Secretary shall pay to the surviving spouse of each Indian War veteran who met the service requirements of section 1511 of this title a pension at the following monthly rate:

(1) $40.64 if such surviving spouse is below seventy years of age; or

(2) $70 if such surviving spouse is seventy years of age or older.

(b) If there is a child of the veteran, the rate of pension paid to the surviving spouse under subsection (a) shall be increased by $8.13 per month for each such child.

(c) No pension shall be paid to a surviving spouse of a veteran under this section unless such surviving spouse was married to such veteran—

(1) before March 4, 1917; or

(2) for one year or more; or

(3) for any period of time if a child was born of the marriage, or was born to them before the marriage.