Which statement is true about 6to4 tunneling?
A. IPv4 traffic is encapsulated with an IPv6 header
B. the edge router can use locally configured IPv6 address
C. host and routers inside a 6to4 site will need a special code
D. an edge router must use IPv6 address of 2002::/16 in its prefix
D
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/interface/configuration/xe-3s/ir-xe-3s-book/ip6-6to4-tunls-xe.html
The tunnel destination is determined by the IPv4 address of the border router extracted from the IPv6 address that starts with the prefix 2002::/16, where the format is 2002:border-router-IPv4-address ::/48. Following the embedded IPv4 address are 16 bits that can be used to number networks within the site.