Python ASAP

What does the following recursive function do, when it is called with a non-empty list as the first parameter and its length as the second parameter? def boo(a, n): "' (list, int) -> bool a is a list of length n if (n == 6 ): res = True else: if a[n-1] == 9: res = boo(a, n-1) else: res = False return res O a) Returns True if all the elements of the list are non-zero, and False otherwise 0 b] Returns True if all the elements of the list are zero, and False otherwise 0 :2) Returns the number of elements that are equal to zero 0 d) Returns the number of elements that are different from zero 0 e) None of the above