A sphere of the radius 7 in. is placed inside a rectangle prism with length 15 in., width 18 in., and height 20 in. What is the volume of the prism not occupied by the sphere? A. 3963.2 in.^3 B. 4028.0 in.^3 C. 4784.2 in.^3 D. 5224.1 in.^3​