Trying to solve the following problem based on the below program. It's from Chapter 2 in Computer Systems (Fourth Edition) by J. Stanley Warford Section 2.4 . The function sum in Figure 2.25 is called for the first time by the main program. From the second time on it is called by itself. "(a) How many times is it called altogether? (b) Draw a picture of the main program variables and the run-time stack just after the function is called for the third time. You should have three stack frames. (c) Draw a picture of the main program variables and the run-time stack just before the return from the call of part (b). You should have three stack frames, but with different con- tents from part (b) Figure 2.25 A recursive sum of the array include using namespace std: int 11st[4]: int sum (int al]. int n) ( 77 Returns the sum of the elenents of a between at0] and atmj. f (n-0) return at0]: else ( return ain]+sum(a.n-1): / ra2 int main O cout 11st[0]> 11st[1] >>11st(2] >> 11stt3]: cout