its operating system solve it by using the language C if its necessary

Problem2 (40 pts) Given 3 concurrent processes P1, P2 and P3, we suppose that initially the share variable x =4. a) List all the possible values for x. (15 pts) b) Use one or more semaphores (use primitives signal and wait) in order to get x=13. (15 pts) c) Can we use only one semaphore to get x=11? Explain your answer. (10 pts) P1 P2 P3 x++; x=x-2 x=x*3