A network engineer notices inconsistent Cisco Discovery Protocol neighbors according to the
diagram that is provided. The engineer notices only a single neighbor that uses Cisco Discovery
Protocol, but it has several routing neighbor relationships. What would cause the output to show
only the single neighbor?

A.
The routers are connected via a Layer 2 switch.

B.
IP routing is disabled on neighboring devices.

C.
Cisco Express Forwarding is enabled locally.

D.
Cisco Discovery Protocol advertisements are inconsistent between the local and remote
devices.