Illinois Real Estate Practice Exam.

The correct term to describe a portion of a building that is constructed on another person's land is "encroachment." Encroachment occurs when a structure, such as a fence or part of a building, intrudes onto a neighbor's property without permission. This can lead to legal disputes, as the property owner has rights to their land, and any unauthorized use can be considered a violation of those rights. The other options refer to different concepts in real estate. Area preference pertains to the desirability of a location, life estate is a form of property ownership that lasts for the lifetime of a designated individual, and a conventional life estate is a specific type of life estate where the rights are limited to that individual's life. These terms do not relate to the unauthorized occupation of land by construction, making encroachment the accurate term in this context.