Suppose that
\dfrac{2 x}{3}-\dfrac{x}{6}
is an integer. Which of the following statements must be true about x ?
Answer Choices
A. It is negative.
B. It is even, but not necessarily a multiple of 3 .
C. It is a multiple of 3 , but not necessarily even.
D. It is a multiple of 6 , but not necessarily a multiple of 12 .
E. It is a multiple of 12 .