A rectangular box is twice as long as it is wide. The height of the box is 3 feet less than the width. If the box is x feet wide, what polynomial represents its volume in cubic feet?
A)4x-3
B)2x^3+6^2
C)2x^2-6x
D)2x^3-6x^2
A)4x-3
B)2x^3+6^2
C)2x^2-6x
D)2x^3-6x^2