**Que:**Box P and Box Q each contain many red balls and white balls. All of the white balls have the same radius. The radius of each white ball is 6 inches less than the average radius of the balls in Box P and 3 inches greater than the average radius of the balls in Box Q. What is the difference between the average (arithmetic mean) radius, in inches, of the balls in Box P and of the balls in Box Q?

(A) 3

(B) 4

(C) 6

(D) 8

(E) 9