After inhalation of an aerosol by a spontaneously breathing patient with no artificial airway, a proportion of the aerosol does which of the following? 1. Impacts in the oropharynx 2. Is swallowed 3. Is absorbed by the lungs 4. Is exhaled

a. 1 and 2 only
b. 1 and 3 only
c. 1, 2, and 3 only
d. 1, 2, 3, and 4

ANS: C