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

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

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

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

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

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

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