D is the answer I believe
There are exactly 5,108 years beteen 3200 B.C.E. (Before current era) and 1903 C.E (Current Era). This is because if we take into consideration that BCE time takes place before year 0 and CE time takes place after; we must calculate the ammount of time it takes to get to year 0 then to the CE time.
A
It’s the most straightforward so that is probably the answer. I can’t see how you could get a more accurate answer other than literally timing each board
They must register for the Selective Service at the age 18, or (when they have received citizenship later), between age 18-26.