Is a 3 digit number divisible by 6?
1) The sum of tens and hundreds' digit is 6.
2) Unit digit is 6.
to be divisible by 6 must be divisible by 3 and to be even
insuff. not info about unit so no idea if is even or if the addition of the 3 digits is a multiple of 3
from (2) not enough either, the 3 digit numbre might not be divisible by 3
yes is sufficient
so I'll go with C