Disk requests arrive at the disk driver for cylinders, 45, 97,21,43,11,69,81,8,55,14,78,74, and 7. A seek takes 5 milliseconds per cylinder moved. Assume that the arm starts initially at cylinder 50 and was moving downward.
How much seek time is needed for:
A) First-come, first served.
B) Closest cylinder next.
C) Elevator algorithm.