Answer: D. Square feet of floor space
Explanation:
The building maintenance cost should be based on a measure that takes into account the size of the building so that the maintenance cost can be apportioned based on how much space needs to be maintained.
The best measure to do so would therefore be the square feet of floor space. If maintenance cost is assigned per square feet, it would take into account how much expenses are being incurred to maintain the entire size of the building.
