The correct answer is: B. cylinder, track, sector data
Cylinder, track, sector data is a disk concept for reducing time lost from rotational delay. It divides the disk into a series of concentric cylinders, each of which contains a series of tracks. Tracks are further divided into sectors. This allows the disk controller to read or write data from any sector on any track without having to wait for the disk to rotate to the correct position.
Fixed block addressing is a method of storing data on a disk in which each block of data is assigned a unique address. This allows the disk controller to quickly locate and access any block of data.
Staggered addressing is a method of storing data on a disk in which the sectors on each track are not aligned with each other. This reduces the amount of time lost due to rotational delay when reading or writing data.
Graduated block identification is a method of storing data on a disk in which the size of each block of data is variable. This allows the disk controller to more efficiently use the available space on the disk.
None of the above options are disk concepts for reducing time lost from rotational delay.