Which of the following does NOT describe a day of personal use?

1. The property owner rented his house to his employer for $50 a day. The fair market rental value is $75 a day.

2. The owner's brother stayed on the property for a week paying $500. The fair market rental value is $500 a week.

3. The owner's mother stays on the property all year paying $600 a month rent. The property is the mother's principal residence and the fair market rental value is $600 a month.

4. The owner rents his mountain property to an outside party for $500 a week in exchange for staying at their lakefront property for $750 a week. The fair market rental value of the mountain house is $500 a week.