Suppose a round-robin scheduling algorithm is used to schedule a set of processes on a single processor. Which of the following statements about the algorithm is true?

A. The quantum size used by the algorithm has no effect on the turnaround time of the processes.

B. The algorithm is not fair because longer processes may have to wait longer than shorter processes.

C. The algorithm is not suitable for real-time systems because it does not guarantee a minimum response time.

D. The algorithm is not optimal because it may not give the shortest average waiting time for all sets of processes. E. The algorithm can be modified to give priority to processes with a higher CPU burst time.