c) Suppose a critical section requires two resources: A and B. Further, suppose that resources A and B are to be protected by semaphores sem_A and sem_B. How would the threads use these semaphores (by calling wait() and signal() on these semaphores) to achieve mutual exclusion while executing the critical section. You have to make sure that the threads wont end up in a deadlock situation. Now, show a way of using the semaphores that may result in a deadlock (1 point). Your answers should include sufficient explanation.

d) Suppose multiple (more than 5) threads are trying to enter a critical section and we want at most 5 threads to execute the critical section at any point in time. Explain how the threads could use a semaphore to achieve this behavior.