Which one of the following statements is true?
(A) If a number is divisible by 3, it must be divisible by 9.
(B) If a number exactly divides the sum of two numbers, it must exactly divide the two numbers separately.
(C) A number is divisible by 18, if it is divisible by both 3 and 6.
(D) None of these
How can C be the correct answer as 12 is also divisible by both 3 and 6 and not divisible by 18