Backbones that connect businesses to WANs, the Internet, and other businesses, usually via SONET networks, are called:

A.
MANs

B.
WANs

C.
VPNs

D.
VLANs

Explanation:
Metropolitan area networks (MAN) typically use SONET or FDDI rings to
connect businesses to the wide area network (WAN), other MANs, the Internet, and the
telecommunication networks. They are referred to as backbones because of the high
speed at which data can travel over them compared to LAN type transmissions.