What does the term plumbing specifically refer to?

The term plumbing specifically refers to the system of pipes, fixtures, and other apparatuses that are installed in a building to distribute water for drinking, heating, washing, and sewage. This definition emphasizes the primary function of plumbing: the transportation and proper management of water flow.

In the context of the choices provided, the correct answer highlights the essential purpose of plumbing systems in residential and commercial settings. While other systems, such as those dealing with gas or electrical wiring, involve pipes or conduits, they do not constitute plumbing in the traditional sense, which is fundamentally centered around water delivery and waste removal. Therefore, plumbing directly relates to the pipes specifically designed for carrying water, making this choice the most accurate description of the term.