What aspect of multicast network transmission allows only intended recipients to receive a signal?

The correct answer focuses on IGMP snooping, which is a critical aspect of multicast network transmission. This feature enables network switches to listen in on the Internet Group Management Protocol (IGMP) communications between hosts and routers. By doing so, the switch can keep track of which devices have joined specific multicast groups.

This tracking allows the switch to intelligently forward multicast traffic only to the ports where there are devices that have expressed interest in receiving that particular multicast stream. Consequently, this minimizes unnecessary traffic on the network and ensures that only intended recipients receive the multicast signals, thus enhancing efficiency and reducing bandwidth consumption.

The other options, while related to networking, do not specifically address the direct control of multicast traffic delivery to specific devices in the way that IGMP snooping does. UDP protocol is mainly concerned with the transport of data but does not manage how multicast destinations are determined. VLAN tagging provides a way to segment network traffic but doesn’t specifically control multicast delivery. Traffic filtering generally refers to the broader practice of controlling traffic based on specific criteria, but it is not exclusive to multicast traffic and does not inherently manage subscriptions to multicast groups.