Given the processes and their burst time ((p1.6),(p2.8) .(p3.7),( p4,3), answer parts a, b, c, and d below: a. Draw the Gantt chart and compute the average waiting time (AWT) if processes arrive in the order pl.p2.p3,p4 (FCFS). b. Draw the Gantt chart and compute the average waiting time (AWT) if processes are executed based on the algorithm of SJF (non-preemptive). c. Draw the Gantt chart and compute the average waiting time (AWT) if processes use Round-robin (RR) algorithm with quantum time of 3 d. Repeat c when time quantum is 6.