A _____ is simply an arrangement where multiple disk drives appear as a single disk drive to the user.

Answer: Option B

disk array : A disk array is a hardware element that contains a large group of hard disk drives (HDDs). It may contain several disk drive trays and has an architecture which improves speed and increases data protection. The system is run via a storage controller, which coordinates activity within the unit. Disk arrays form the backbone of modern storage networking environments. A storage area network (SAN) contains one or more disk arrays that function as the repository for the data which is moved in and out of the SAN.

Source : wikipedia.org