What is the conclusion of the following conditional?

A number is divisible by 3 if the sum of the digits of the number is divisible by 3/

A. The number is odd.
B. The sum of the digits of the number is divisible by 3.
C. If the sum of the digits of a number is divisible by 3, then the number is divisible by 3.
D. The number is divisible by 3.