This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of these is a definitive airway: 
Select and explain. 
A. Orotracheal airway., B. Nasopharyngeal airway., C. Nasotracheal airway., D. LMA.
C: Nasotracheal airway.
Answer: C: Nasotracheal airway. 
Explanation: None