What is a wide-area network (WAN)?

What is a wide-area network (WAN)?

A.
A network that connects client devices wirelessly using radio waves

B.
A network that crosses metropolitan, regional, or national boundaries

C.
A network that is restricted to a single building, a group of buildings, or even a single room

D.
A network that encompasses an entire city or metropolitan area and connects multiple local- area networks (LANs)