(2) If the purpose of the entry is to exhibit the dwelling unit to prospective or actual purchasers, the notice may be given orally, in person or by telephone, if the landlord or his or her agent has notified the tenant in writing within 120 days of the oral notice that the property is for sale and that the landlord or agent may contact the tenant orally for the purpose described above. Twenty-four hours is presumed reasonable notice in the absence of evidence to the contrary. The notice shall include the date, approximate time, and purpose of the entry. At the time of entry, the landlord or agent shall leave written evidence of the entry inside the unit.