Which of the Following Statements Regarding Personal And/or Rental Use

Which of the following statements regarding personal and/or rental use of a home is false?

A) A day for which a taxpayer rents a home to an unrelated party for less than the property's fair market value is considered to be a personal-use day.
B) A day for which a taxpayer rents a home to a relative for full fair market value is considered to be a rental use day (home is not the relative's principal residence) .
C) A day for which an unrelated nonowner stays in the home under a vacation exchange arrangement is considered to be a personal-use day.
D) A day for which the home is available for rent but is not occupied does not count as a personal-use or a rental use day.