Which expression is not equivalent to the following expression?

15 - 3 + 15 - 3 - 3 + 15

A. 3 (15 - 3)

B. 3 (15)

C. 3 (15 + 3)

D. 3 (12)

In the above problem: it appears that the original expression is equal to 36.

A. 3 (15-3) = 3 (12) = 36

B. 3 (15) = 45

C. 3 (15+3) = 3 (18) = 54

D. 3 (12) = 36

So it looks like choices A and D are equivalent to the original expression.