Which statement best describes NAS?

A.
NAS is a network architecture that refers to storage elements that connect to a network and provide file-level access services to computer systems.

B.
NAS is a network architecture that refers to storage elements that connect to a network and provide block level access services to computer systems.

C.
NAS is a network that uses an encapsulated SCSI protocol.

D.
NAS is a network for large enterprise customers.

Explanation:
http://en.wikipedia.org/wiki/Network-attached_storage