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: Dental
All of the following factors alters buccinator mechanism EXCEPT 
Select and explain. 
A. Mouth breathing, B. Thumb sucking, C. Tongue thrusting, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Habits that alter the buccinator mechanism are

Mouth breathing
Thumb/Finger sucking
Tongue Thrusting
Lip/Nail Biting