The answer is B.
Step-by- step explanation:
The sum of 231 is 6
6 is divisible by 3
If the sum of a number is divisible by three, the number is divisible by 3
Divisibility rules
Rules of 2: the number is divisible by 2 if it ends with 0,2,4,6 and 8
Rules of 5: the number is divisible by 5 if the number ends with 0 or 5
Rules of 9: of the sum of the number is divisible by 9, the number is divisible by 9
Hope this helps <3