What allows for multiple viewers to enjoy the same program concurrently?

Multicast distribution is the correct answer because it enables the delivery of data to multiple recipients simultaneously over a network. In a multicast setup, a single stream of data is sent to a group of users who wish to receive the same content at the same time. This method efficiently uses network resources, as it avoids the need to send separate streams to each viewer, allowing for a more streamlined and effective way to broadcast live events or programs to many users concurrently.

In contrast, while adaptive streaming optimizes the delivery of video content based on a viewer's bandwidth and device capabilities, it does not inherently allow for multiple users to watch the same content at the same time. Exclusive broadcasting refers to situations where a program can only be accessed by a single viewer, which contradicts the idea of multiple people watching at once. On-demand functionality provides viewers the ability to watch content at their convenience but does not imply concurrent viewing; rather, it allows for individual access whenever the viewer chooses. Thus, multicast distribution directly addresses the need for simultaneous viewing by multiple users.