How is a one-family dwelling described?

A one-family dwelling is defined as a building that consists solely of one dwelling unit. This means it is designed to accommodate a single household or family. The focus is on the exclusivity of the dwelling unit, which is separate from others, ensuring that it serves one family or household without sharing living spaces with other units.

This definition is crucial in the context of the National Electrical Code, as various requirements and standards apply specifically to residential structures. Knowing that a one-family dwelling is a standalone unit helps in understanding the different safety, electrical installation, and compliance issues that may arise.

Other descriptions like structures with three or more units or buildings consisting of two dwelling units do not match the definition of a one-family dwelling as they pertain to multi-family or mixed-residential units, which have different regulatory and design considerations under the NEC. A multi-tenant building also implies multiple separate units, further differentiating it from a one-family dwelling. Thus, B is the correct choice because it accurately encapsulates the essence of a one-family dwelling within the framework defined by the NEC.