Massachusetts Plumbers Journeyman Practice Exam

A combination waste-and-vent system is the correct answer because it is a type of plumbing system that is limited to the installation of only floor drains and sinks. This system is designed to safely remove waste from these specific fixtures and allow for proper venting to prevent sewer gases from backing up into the building.

The other options are incorrect because:

A. A waste and vent system is designed to handle both waste removal and venting for a variety of fixtures, not just limited to floor drains and sinks.

C. A vent-only system is solely for providing venting to allow air to enter the plumbing system to facilitate proper drainage. It does not handle waste removal like the combination waste-and-vent system.

D. A drainage system is a broad term that encompasses all piping used to remove wastewater from a building, including floor drains and sinks, as well as toilets, showers, and tubs.