Seek Time:
Seek time is the time taken by the disk arm to position itself over the track where the data is stored. It is the time required to move the read/write head to the correct track on the disk. Seek time is a major part of the time taken when accessing data on the disk.

Rotational Latency:
Rotational latency is the time taken for the desired sector to rotate under the read/write head. It is the time required for the disk to rotate to the correct sector. Rotational latency is also a significant part of the time taken to access data on the disk.

Settle Time:
Settle time is the time required for the read/write head to stabilize over the correct track and sector. It is the time needed for the head to settle before data can be read or written. Settle time is a part of the overall access time but is usually much smaller compared to seek time and rotational latency.

Waiting Time:
Waiting time refers to the time spent waiting for the disk to be ready for the next operation. It includes the time required for the disk controller to initiate the operation and any other delays in the system. Waiting time can vary depending on the system's load and other factors.

Conclusion:
Among the given options, seek time is the major part of the time taken when accessing data on the disk. It involves moving the read/write head to the correct track where the data is stored. Rotational latency and settle time also contribute to the overall access time, but seek time usually accounts for the majority of the time. Waiting time, on the other hand, is not directly related to the disk's mechanical operations but includes other system delays.