Final answer:
Multicast is the type of communication where a computer sends messages to a specific group of computers on a network, which is distinct from unicast, broadcast, and anycast methods.
Step-by-step explanation:
When a computer in a given network communicates with a specific group of computers, the type of communication is called multicast. Unlike unicast, where one sender communicates with one receiver, or broadcast, where the communication is sent to all nodes on the network, multicast is a more efficient method where communication is addressed to a specific group of interested receivers. An example would be a video conference where the feeds are only sent to defined participants, not to all the computers on a network. Another type, anycast, is used when a message is sent to any one of a group of nodes, typically the nearest one in networking terms. Thus, the correct answer to the student's question is option 3) Multicast.