The correct answer is B. DBLSPACE.
DBLSPACE is a DOS command that allows you to compress existing disks and to create new compressed volumes. It is a disk compression utility that can be used to compress files and folders on a hard disk. DBLSPACE can also be used to create compressed volumes, which are logical drives that are stored on a compressed partition.
DEFRAG is a DOS command that defragments a disk. Defragmentation is the process of rearranging the data on a disk so that it is stored in contiguous blocks. This can improve the performance of a disk by making it faster to access data.
SCANDISK is a DOS command that scans a disk for errors. SCANDISK can also be used to repair errors on a disk.
MSAV is a DOS command that scans a disk for viruses. MSAV can also be used to remove viruses from a disk.
None of the above options are correct.