Which of the following protocols is used by IPv6 for MAC address resolution?

NDP (Neighbor Discovery Protocol), defined in RFC 4861, is the IPv6 equivalent of IPv4's ARP and performs MAC address resolution via Neighbor Solicitation and Neighbor Advertisement ICMPv6 messages. NDP also handles router discovery, prefix discovery, and stateless address autoconfiguration. It is built directly into ICMPv6 rather than being a separate protocol like ARP.

ARP (Address Resolution Protocol) is used exclusively in IPv4 networks to resolve IP addresses to MAC addresses and is not used in IPv6 - NDP replaces it entirely.

DNS (Domain Name System) resolves human-readable hostnames to IP addresses and has no role in resolving IP addresses to MAC addresses at the data link layer.

NCP (Network Control Protocol) is a component of the PPP protocol suite used to negotiate network layer parameters and is unrelated to address resolution in IPv6.