Which method of mass storage automatically puts often used data onto an online source, while storing less used data on a near-line source such as a tape system?

Which method of mass storage automatically puts often used data onto an online source, while
storing less used data on a near-line source such as a tape system?

A.
SAN (Storage Area Network)

B.
HSM (Hierarchical Storage Management)

C.
RAID (Redundant Array of Independent Disks)

D.
NAS (Network Attached Storage)