Help Me plz Im stuck

Which is the counterexample to the following conjecture?

If a number is divisible by 3, it must also be divisible by 9.

A.18


B.54


C.21


D.27

Respuesta :

The answer is C.
21 is divisible by 3 but not by 9.
21 = 3*7 . . . . . divisible by 3, but not by 9

The appropriate selection is C. 21