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
Lip bumper not used in the treatment of 
Select and explain. 
A. Lip biting, B. Distalisation of molars, C. Nail biting, D. Lip exercises
C: Nail biting
Answer: C: Nail biting 
Explanation: None