You have two facilities and both use IPv6 addressing internally. However, both facilities are connected to the Internet via IPv4. What is one recommended method you can use to communicate between the facilities over the Internet?

A. Dedicated leased line
B. Frame Relay
C. Dual stack
D. 6to4 tunnel

D. A 6to4 tunnel can be achieved between the routers. This encapsulates the IPv6 header in an IPv4 header so that it can be routed across the Internet.