If all OSPF routers in a single area are configured with the same priority value, what value does a
router use for the OSPF router ID in the absence of a loopback interface?

A.
the IP address of the console management interface

B.
the IP address of the first Fast Ethernet interface

C.
the highest IP address among its active interfaces

D.
the lowest IP address among its active interfaces

E.
the priority value until a loopback interface is configured

Explanation:
Ordinarily the loopback interface would be selected as the router ID. In the event that no loopback
interface is configured, the router ID will be the first active interface that comes up on the router. If
that particular interface has more then one IP address, then the highest address will be selected
as the Router ID.