The tracks on a disk which can be accessed without repositioning the R/W heads is

The correct answer is B. Cylinder.

A cylinder is a set of tracks on a disk that are all at the same radius. The R/W heads do not need to be repositioned to access tracks on the same cylinder, which makes it the fastest way to access data on a disk.

A surface is a single side of a disk platter. The R/W heads need to be repositioned to access tracks on different surfaces.

A cluster is a group of sectors on a disk. The operating system uses clusters to store files.

E. None of the above is incorrect because a cylinder is a set of tracks on a disk, not a single track.