Storage arrays that are used with backup applications and emulate tape systems is commonly referred to as which of the following?

D2D2T (Disk-to-Disk-to-Tape) is a backup strategy that first backs up to disk, then to tape, not a type of storage array that emulates tape.

A Virtual Tape Library (VTL) is a data storage virtualization technology that appears to a backup server as a tape library and tape drives, but actually stores data on disk arrays. This allows backup applications to use disk-based storage for faster backups and restores while retaining their existing tape-based backup logic and configurations.

LTO (Linear Tape-Open) is a magnetic tape data storage technology for actual physical tape cartridges and drives, not a virtual emulation system.

ATM (Asynchronous Transfer Mode) is a switching technique for telecommunication networks, completely unrelated to storage array emulation.