An IPv6 network is under attack from a source not in the binding table and not learned via neighbor discovery. Which feature helps prevent this attack?

IPv6 Prefix Guard prevents attacks from sources not in the binding table or learned via Neighbor Discovery by ensuring that traffic from a host is only forwarded if the source IPv6 address is from a prefix assigned to the link. This protects against spoofed source addresses that do not belong to the local subnet. IPv6 Destination Guard protects against traffic to destinations not in the binding table. IPv6 Router Advertisement Guard prevents malicious or unauthorized RA messages. IPv6 Snooping tracks Neighbor Discovery messages to build a binding table, but doesn't directly prevent attacks from sources not learned via ND or in the binding table if the source address is outside the local prefix.