What is one similarity between a flag lot and a key lot?

The correct choice highlights a significant aspect of both flag lots and key lots related to their dimensions and compliance with current building codes. Flag lots and key lots typically have unique shapes and dimensions that can restrict the use of the land. The narrow frontages that are characteristic of these lot types often make it challenging to meet the building codes that govern setback requirements, lot coverage, and other factors that ensure safety and proper use of the property. This can lead to situations where the structures built on these lots may not conform to modern building codes.

In contrast, the other options either do not accurately define a similarity between the two lot types or involve characteristics that are too specific or variable. For instance, while both types of lots could potentially have swimming pools, that feature is not a defining aspect of their classification. The shape of flag and key lots can also vary; they are not specifically required to be rectangular, and their geography is not limited strictly to suburban areas, as they can also be found in urban or rural settings. Thus, the focus on narrow lot dimensions and their implications for code compliance accurately captures a fundamental similarity between these lot types.