Consider the following set of processes, with the length of the CPU burst time given in milliseconds: Process Arrival Time Burst Time Priority 15 a. Draw four Gantt charts that illustrate the execution of these processes using the following scheduling algorithms: FCFS, SJF (preemptive), Priority Queues (higher priorities run first (non-preemptive) and RR (9= 3). b. What is the waiting time of each process for each of these scheduling algorithms? c. Which of the algorithms results in the minimum average waiting time (over all processes), why