A municipality adopts a zoning ordinance that restricts a neighborhood to single family residences only. A person owns a two-family house in the same neighborhood at the time the ordinance is adopted. Which of the following must this owner do?

Appealing for a variance is unnecessary because the owner is already in possession of a legally established two-family home. A variance is typically sought to deviate from current zoning laws for new constructions, not to maintain existing structures that do not conform to new regulations.

The owner is not obligated to convert the two-family house into a single-family residence, as the existing use is grandfathered under the ordinance. The property can continue to function as a two-family home without any conversion, preserving the owner's rights under the previous zoning regulations.

Applying for an exercise of eminent domain is irrelevant in this situation as it pertains to government acquisition of private property for public use, usually with compensation. The owner is not facing any government action that would necessitate such a process; rather, they are simply dealing with a change in zoning laws that affects future development.