Within OSPF, what functionality best defines the use of a ‘stub’ area?

A.
It appears only on remote areas to provide connectivity to the OSPF backbone.

B.
It is used to inject the default route for OSPF.

C.
It uses the no-summary keyword to explicitly block external routes, defines the non-transit area, and uses the default route to reach external networks.

D.
It is a non-transit area that does not allow flooding of external networks and uses the default route to reach external networks.