I. Consider a single CPU system with an active process A. Explain what happens in the following circumstances including any interrupts, system calls, etc.. and how they are handled until a process is back to running again (4.5 points) a) A process executes continuously until it exhausts its scheduler allocated time slice b) A packet writes to an open file (note that we don't have to wait for a response, so no waiting state) c) A process does an illegal operation such as accessing a null pointer