Which of these is true regarding tunnel configuration when deploying a Cisco ISR as a DMVPN hub router?
A. Only one tunnel can be created per tunnel source interface.
B. Only one tunnel can be created and should be associated with a loopback interface for dynamic redundancy
C. The GRE tunnel key is used to encrypt the traffic going through the tunnel through the hub.
D. You can run multiple parallel DMVPNs on the hub router, but each tunnel requires a unique tunnel key.
