A voice coach charges $165 for 1.5 hours of work. Which proportion can be used to find x, the number of dollars the voice coach charges for 4 hours of work?

A. x/4 = 1.5/165
B. x/165 = 3.5/2.5
C. x.165 = 1.5/4
D. x/4 = 165/1.5