Why is a disk-to-disk-to-tape (D2D2T) backup environment normally used?

A.
to synchronize online backups of databases and to automatically overwrite transaction logs

B.
to stage backup data to a host-managed, low-cost disk and to facilitate quick restores

C.
to enable backups and restores of virtual machines without disrupting virtual applications, and to
maximize snapshot performance

D.
to create virtual backups of ESX servers and to enable snapshot restores