You attempt to build an OSPF virtual link between two ABR routers and it fails to form.
What are three explanations for this? (Choose three.)
A.
Both routers must share a common area.
B.
An adjacency exists with secondary IP addressing.
C.
An adjacency exists over an asynchronous interface.
D.
The transit area cannot be a stub area.
E.
One of the ABRs must be connected to area 0.