Layer 3 switches do a good job of containing which of the following?

Layer 3 switches are designed primarily for routing and managing traffic between different networks or subnets at the network layer of the OSI model. One of their key functionalities is to handle and contain broadcast traffic effectively. Since broadcasts are sent to all devices within a network and can lead to excessive traffic if not properly managed, Layer 3 switches can segment networks into smaller subnets. This segmentation limits the broadcast domain, allowing broadcasts to be contained within specific subnets rather than flooding the entire network, thus improving overall network efficiency and performance.

Regarding the other types of traffic, while Layer 3 switches can handle unicast and multicast traffic, they don't perform the same containment function as they do with broadcasts. Unicast traffic is directed to a single destination and operates independently, while multicast traffic is meant for a defined group of devices. As such, the Layer 3 switch plays a different role in those contexts, primarily focusing on routing rather than containment. Thus, the ability of Layer 3 switches to effectively manage and contain broadcast traffic makes that option the correct choice in this instance.