Consider the following pseudocode, where S is a semaphore initialized to 5 in…

Consider the following pseudocode, where S is a semaphore initialized to 5 in line #2 and counter is a shared variable initialized to 0 in line #1. Assume that the increment operation in line #7 is not atomic. 

int counter =0;

Semaphore S= init(5);

void parop(void)

{

           wait(S);

           wait(S);

           counter++;

           signal(S)

           signal(S);

     }

If five threads execute the function parop concurrently, which of the following program behavior(s) is/are possible?