Which of the following characteristics describes a Source-Based Distribution Tree?

A Source-Based Distribution Tree is characterized by the fact that the source of the multicast traffic acts as the root of the tree. In this type of distribution tree, the multicast traffic flows from the source to all interested receivers by replicating the traffic at each branch in the tree structure. This approach is effective for ensuring that all receivers receive the traffic directly from the source, which can enhance bandwidth efficiency for particular types of multicast traffic patterns.

The other characteristics provided in the options relate to different types of multicast routing or network topology configurations. For example, the use of a rendezvous point pertains to a Shared Tree, where all multicast traffic is routed through a central point before being distributed, differing from the source-based approach. Additionally, the requirement for unicast routing and the stipulation concerning all nodes being on the same subnet do not apply to Source-Based Distribution Trees, as these trees can span across networks and utilize multicast routing protocols that can operate in various scenarios, including interconnected subnets.