One of your router’s OSPF adjacencies is down.
What are three reasons for this adjacency state change? (Choose Three)

A.
A filter has just been configured on one of the OSPF routers.

B.
The OSPF hello value is the same on both routers.

C.
The controlling BFD session state has gone down.

D.
The authentication key on both routers matches.

E.
One of the physical interfaces has gone down.

Explanation: