Evaluate the Double Integral by First Identifying It as the Volume

Multiple Choice

Evaluate the double integral by first identifying it as the volume of a solid.
$$\iint _ { R } ( 15 - 2 x ) d A , R = \{ ( x , y ) \mid 4 \leq x \leq 7,2 \leq y \leq 6 \}$$
Select the correct answer.

A) $- 120$
B) 280
C) 180
D) $- 20$
E) 80