Final answer:
The proper description of a vast piece of property with only an abandoned and heavily deteriorated barn would be land.
Step-by-step explanation:
The proper description of a vast piece of property with only an abandoned and heavily deteriorated barn would be D) The property would be called land. In this scenario, the barn is not considered an improvement and would likely need to be razed, making it irrelevant to the overall description of the property. Therefore, the most appropriate term to describe such a property is 'land'.