Which command is used to configure an IPv6 anycast address on a router interface?

The command to configure an IPv6 anycast address on a router interface is specifically designed to define the address type accurately. The correct command includes the term 'anycast,' explicitly indicating that the address being configured will be treated as an anycast address.

In IPv6, anycast addresses are intended to be assigned to multiple interfaces, typically on different devices, with the routing mechanism ensuring that packets are delivered to the nearest or most optimal interface available. This makes the identification of the specific type of address critical during configuration. The syntax in the correct command clearly specifies that the address type being set up is an anycast address, which is essential for the intended routing behavior.

The other options incorrectly identify the address type as either unicast or multicast or do not include proper syntax for addressing anycast. Unicast refers to a single destination, while multicast is used for sending packets to multiple specific destinations. Since anycast serves a different purpose in routing, those alternative commands do not appropriately configure an anycast address and would not function as intended.