Multifamily structures are a structure that ________.

The definition of multifamily structures is centered around the concept of multiple living units within one building or complex. Therefore, the correct option accurately reflects that multifamily structures consist of two or more individual units.

In a multifamily building, these separate units can take various forms, ranging from apartment complexes to condominiums and any other arrangements where multiple families live close together under one roof. This classification allows for shared amenities and often results in a more efficient use of space and resources than single-family homes.

The other options are too restrictive or specific. For instance, stating that multifamily structures consist of only single-family units contradicts the very concept of multifamily housing. Similarly, limiting the definition to townhouses or duplexes excludes other types of multifamily buildings that also fit the definition, such as apartment buildings or triplexes. Thus, recognizing that multifamily structures encompass a broader category involving two or more individual living spaces is essential for understanding the scope of this type of housing.