Which of the following is NOT classified as a commercial comparative unit?

The concept of commercial comparative units refers to measurements commonly used in the evaluation of commercial properties to provide a standard basis for comparison in appraisals, leases, and real estate transactions.

Gross Building Area includes all floor space within the outer walls of the building and is often used in the valuation process because it encapsulates the total size of commercial properties. Net Rentable Area and Net Leaseable Area refer to the space that can be rented out to tenants, excluding common areas, which is significant in assessing a property's income-generating potential.

On the other hand, Net Floor Area is typically defined as an area that is calculated by measuring the areas within the exterior walls and usually includes all usable space, which can also align with operational considerations.

The choice identified as not classified as a commercial comparative unit is Net Floor Area. This designation is often more closely associated with residential property calculations or specific types of building regulations rather than serving as a standardized measurement in commercial property comparisons. Therefore, while it has its uses, it doesn't fit neatly into the typical comparative units used specifically in commercial real estate valuations, thus making it the correct answer.