The following code is supposed to return the sum of the numbers between 1 and n inclusive, for positive n. An analysis of the code using our "Three Question" approach reveals that: int sum(int n){
if (n == 1)
return 1;
else
return (n + sum(n - 1));
}

a. it fails the base-case question.
b. it fails the smaller-caller question.
c. it fails the general-case question.
d. it passes on all three questions and is a valid algorithm.
e. None of these is correct.