What type of raceway is described as a lightweight, prefabricated conduit system used in commercial settings?

The description of being a "lightweight, prefabricated conduit system used in commercial settings" applies best to cablebus systems. Cablebus is designed to accommodate a variety of electrical conduit needs, providing a tray-like structure that allows for the safe routing of multiple cables. These systems are recognized for being flexible and capable of handling different cable arrangements.

In many commercial environments, the ease of installation and adaptability of cablebus systems make them an ideal choice. They often come pre-assembled or can be quickly adapted on-site, which saves both time and labor costs during installation.

While other options like metal wireways and nonmetallic wireways serve specific functions in wiring management, they don't have the same level of lightweight prefabrication or prevalent use across diverse commercial applications as cablebus does. Cellular concrete floor raceways, while useful in particular contexts for embedded installations, also do not match the characteristics described in the question regarding lightweight and prefabrication.