Why would you choose to combine dynamic routing protocols and VPNs?

A.
The VPN device can be automatically updated with network changes on any VPN peer
Gateway without the need to update the VPN Domain’s configuration.

B.
Dynamic-routing information can propagate over the VPN, utilizing the VPN as just another
point-to-point link in the network.

C.
In the case of one tunnel failure, other tunnels may be used to route the traffic.

D.
All options listed.