Consider a concurrent program with two threads, p and q, defined as follows. A, B, C, D, and E are arbitrary atomic (indivisible) statements: semaphore s1, s2;// void p() {// A(); B(); C();// void q() {// D(); E();//}} void main() {parbegin{p, q};//} Show all the possible interleavings of the execution of the preceding two threads by giving execution "traces" in terms of the atomic statements: e.g. ABCDE, ADBCE. (e) Given 2 semaphore s1 and s2, with functions semWait(s) and semSignal(s) for decrement and increment the semaphore respectively, modify the program in part (d) in order to ensure execution sequence of ABCDE