The function \(f\) is defined for each positive three-digit integer \(n\) by \(f(n)=2^x3^y5^z \), where \(x, y,\) and \(z\) are the hundreds, tens, and units digits of \(n,\) respectively. If \(m\) and \(v\) are three-digit positive integers such that \(f(m)=9f(v)f(m)=9f(v),\) then \(m-v=m-v= ?\)

(A) 8
(B) 9
(C) 18
(D) 20
(E) 80

Answer: D

Source: GMAT Paper Tests