Which digit(s) makes 3,71_ divisible by 3?
A. 3 only
B. 7 only
C. 1 only
D. 1, 4, and 7
C. 1 only
A number is divisible by 3 if the sum of its digits is divisible by 3,
a fact apparently not known by the bot
so far we have 3+7+1 = 11
so we can add 1, 4, or 7 and get a sum of 12, 15, and 18
so the correct answer is D