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
Over extension of the posterior border of the denture causes 
Select and explain. 
A. Gagging sensation, B. Epulis fissuratum, C. Sagging of the corners of the mouth, D. All of the above
A: Gagging sensation
Answer: A: Gagging sensation 
Explanation: None