NFPA 1 and 101 define a health care occupancy as an occupancy that provides health or medical services to:

A. persons who may be incapable of evacuating during an emergency without assistance regardless of the number of patients.
B. greater than 20 persons who may or may not be able to evacuate during an emergency without assistance.
C. ten or more individuals at any given time regardless of their ability to evacuate during an emergency.
D. four or more individuals who cannot evacuate themselves during an emergency without assistance.

Answer: D. four or more individuals who cannot evacuate themselves during an emergency without assistance.