18. Consider the following set of processes, with the length of the CPU burst given in milliseconds. p) Draw four Gantt Charts that illustrate the execution of these processes using the following scheduling algorithms: FCFS, SJF Non Preemptive, SJF Preemptive. q) What is the waiting time of each process for each of the scheduling algorithms in part a? r) Which of the algorithms produce results in the minimum average waiting time (Overall Processes)