ANS:B - is used for analyzing device busy problems

Seek time is the time taken for a hard disk controller to locate a specific piece of stored data. Other delays include transfer time (data rate) and rotational delay (latency).

When anything is read or written to a disc drive, the read/write head of the disc needs to move to the right position. The actual physical positioning of the read/write head of the disc is called seeking. The amount of time that it takes the read/write head of the disc to move from on part fo the disk to another is called the seek time. The seek time can differ for a given disc due to the varying distance from the start point to where the read/write head has been instructed to go. Because of these variables, seek time is generally measured as an average seek time.