Why GET VPN is not deployed over the public Internet?

A.
Because the GET VPN group members use multicast to register with the key servers

B.
Because the GET VPN key servers and group members to requires a secure path to exchange
the Key Encryption Key (KEK) and the traffic Encryption Key (TEK)

C.
Because the GET VPN uses IPSec transport mode, which would expose the IP Addresses to
the public if using the Internet

D.
Because the GET VPN preserves the original source and destination IP addresses, which may
be private addresses that are not routable over the Internet