Which one of the following statements about a nasal cannula is true?

A) "I can adjust the oxygen flow rate anywhere from 1 to 8 lpm, depending on how much oxygen the patient needs."
B) "When the nasal cannula is set to the highest appropriate oxygen flow rate, a large portion of the air inspired by the patient is ambient air."
C) "The nasal cannula is preferred over the nonrebreather mask because it gives the oxygen through the nose instead of the mouth."
D) "It is best to see how the patient tolerates the nasal cannula before attempting to place a nonrebreather mask on the patient."

B