public static int func1(int m, int n) {    if (m == n || n == 1)        return 1;    else         return func1(m - 1, n - 1) + n * func1(m - 1, n);}What precondition must exist in order to prevent the code in the accompanying figure from infinite recursion?

A. m >= 0 and n >= 0
B. m >= 0 and n >= 1
C. m >= 1 and n >= 0
D. m >= 1 and n >= 1

Answer: B