A router has a single Ethernet connection to a switch. In the router configuration, the Ethernet
interface has three sub-interfaces, each configured with ACLs applied to them and 802.1q trunks.
Which of the following is MOST likely the reason for the sub-interfaces?

A.
The network uses the subnet of 255.255.255.128.

B.
The switch has several VLANs configured on it.

C.
The sub-interfaces are configured for VoIP traffic.

D.
The sub-interfaces each implement quality of service.

Explanation:
A subinterface is a division of one physical interface into multiple logical interfaces. Routers
commonly employ subinterfaces for a variety of purposes, most common of these are for routing
traffic between VLANs. Also, IEEE 802.1Q is the networking standard that supports virtual LANs
(VLANs) on an Ethernet network.