2. [30] [CPU Scheduling] Process Control: Consider the following 4 processes with arrival time, burst time, and priority as follows: Process Arrival Burst Priority 0 1 2 P1 P2 P3 P4 a) Use preemptive SJF algorithm to draw the Gnatt chart and find the average waiting time. b) Use preemptive priority scheduling algorithm to schedule these processes drawing the 4 resulting Gnatt chart and find the average wait time. Use c) Round Robin method with a time quantum of 2 units and find the average waiting time