Which statement is true concerning 6to4 tunneling?（）

• A、The edge routers can use any locally configured  IPv6 address.
• B、Hosts and routers inside a 6to4 site will need a special code.
• C、An edge router must use IPv6 address of 2002::/16 in its prefix.
• D、IPv4 traffic is encapsulated with an IPv6 header.