NAT-PT (Network address translation-Protocol Translation) is useful when an IPv4-only host needs to communicate with an IPv4-only host. NAT-PT (Network Address Translation-Protocol Translation) is an implementation of RFC 2766 as specified by the IETF. NAT-PT was designed so that it can be run on low-end, commodity hardware. NAT-PT runs in user space, capturing and translating packets between the IPv6 and IPv4 networks (and vice-versa). NAT-PT uses the Address Resolution Protocol (ARP) and Neighbor Discovery (ND) on the IPv4 and IPv6 network systems, respectively.

NAT-Protocol Translation can be used to translate both the source and destination IP addresses. Answer option D is incorrect. Native IPv6 is of use when the IPv6 deployment is pervasive, with heavy traffic loads. Answer option C is incorrect. Point-to-point tunnels work well when IPv6 is needed only in a subset of sites. These point-to-point tunnels act as virtual point-to-point serial link. These are
useful when the traffic is of very high volume.
Answer option A is incorrect. The multipoint tunnels are used for IPv6 deployment even when IPv6
is needed in a subset of sites and is suitable when the traffic is infrequent and of less predictable
volume.