Which three statements are true of GRE tunnels? (Choose three.)

A.
The local tunnel endpoint must have a valid route to the remote endpoint.

B.
GRE tunnels must authenticate at both ends of the tunnel.

C.
Tunnel endpoints must have a route that directs traffic into a tunnel.

D.
The “gr” interface can only route packets that are IP protocol packets.

E.
All intermediary devices must have a route to the tunnel endpoints.