Which of the following is NOT a requirement for plumbing in a dwelling?

The correct answer, which indicates a refrigerator, highlights that it is not a requirement for plumbing in a dwelling. Plumbing requirements typically involve fixtures essential for the function of the plumbing system and meeting health and safety standards. In a standard residential setting, capabilities related to water supply and waste management are prioritized.

Key plumbing fixtures that are generally mandated include the kitchen sink, water closet (toilet), and lavatory (sink). These fixtures are directly associated with the indoor plumbing system as they provide essential functions such as sanitation, hygiene, and convenience. A refrigerator, however, is an appliance used for food storage and does not directly connect to the plumbing system nor does it contribute to the dwelling's core plumbing needs. While it may have a water supply for features like ice makers or water dispensers, its absence does not violate any plumbing codes or basic living requirements, thus making it the correct choice for the answer.