Which of the following could cause external obsolescence?

External obsolescence refers to a loss in property value due to factors outside the property itself, typically related to the surrounding environment or external conditions. Zoning is a significant factor that can lead to external obsolescence because it dictates how land can be used in a particular area. For example, if zoning regulations change and a residential area is re-zoned for commercial use, this could adversely affect the property values of homes in that community.

Additionally, zoning can lead to undesirable changes in the neighborhood, such as increased traffic, noise, or changes in the character of the area. These external factors may detract from the desirability of the property, resulting in reduced market value.

In contrast, architectural design, building deterioration, and a poor floor plan are primarily related to the property itself and are considered forms of internal obsolescence, where issues lie within the structure or design of the building rather than its external environment.