Explanation:

Disk scheduling policies are used to access data from a hard disk in a systematic manner. The main goal of a disk scheduling policy is to minimize the head movement of the disk arm. The three disk scheduling policies are FCFS, Circular SCAN, and Elevator.

FCFS:

FCFS stands for First Come First Serve. In this policy, the disk requests are serviced in the order in which they arrive. The head moves to the first request and then to the second request, and so on until all the requests are serviced. This policy does not consider the location of the requests on the disk. Hence, it may result in a large amount of head movement.

Circular SCAN:

In Circular SCAN, the head moves in a circular manner from one end of the disk to the other end. When it reaches the other end, it immediately moves to the other end in the same direction without servicing any requests. This policy reduces the average waiting time but may result in a large amount of head movement.

Elevator:

In the Elevator policy, the head scans the disk in one direction (either towards the outer edge or the inner edge) until it reaches the end. Then it immediately changes its direction and moves towards the other end, servicing requests along the way. This policy reduces the average waiting time and also results in a minimum amount of head movement.

Conclusion:

Out of the three disk scheduling policies, the Elevator policy results in a minimum amount of head movement.