Let f(x,y) be defined as the remainder when (x–y)! is divided by x. If x=45, what is the maximum value of y for which f(x,y)=0?	Choose the correct choice.
A) 32
B) 35
C) 39
D) 40
E) 42
The question is finding y such that (45-y)! is a multiple of 45. That means we need to have 5*3^2 in (45-y)!   6! is the smallest factorial number with 5*3^2 as a factor.   45-y = 6   y = 39   The answer is 39.
<result>C</result>
Let f(x,y) be defined as the remainder when (x–y)! is divided by x. If x=45, what is the maximum value of y for which f(x,y)=0?