Why has the network shown in the exhibit failed to converge?

A.
The autonomous system number has not been properly configured.

B.
The network numbers have not been properly configured on the routers.

C.
The no auto-summary command needs to be applied to the routers.

D.
The bandwidth values have not been properly configured on the serial interfaces.

E.
The subnet masks for the network numbers have not been properly configured.

Explanation:
To restore the default behavior of automatic summarization of subnet routes into network-level
routes, use the auto-summary command in router configuration mode. To disable this function and
transmit subprefix routing information across classful network boundaries, use the no form of this
command. Without disabling auto summarization, each router will advertise the 192.168.20.0/24
route, and the specific /26 networks will not be known.