With regards to the IPv6 transition mechanism, which two tunneling disadvantages are? (Choose two.)
A. Tunneling techniques are not scalable because they cannot be dynamically created, they must be manually created.
B. Users of the new architecture cannot use the services of the underlying infrastructure.
C. IPv6 needs to be activated on almost of the network elements in the existing network, posing business continuity challenges.
D. Tunneling does not enable users of the new protocol to communicate with users of the old protocol without dual stack hosts, which negates the interoperability.
E. Tunneling provides a gradual migration to IPv6 network by providing seamless Internet experience to greenfield IPv6 only users to access IPv4 Internet services.
