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
The function of posterior palatal seal is: 
Select and explain. 
A. To aid in balanced occlusion, B. To aid in insertion and removal of complete denture, C. To ensure a complete seal thus helping in retention of a denture, D. Retention of mandibular denture by sealing its posterior margin.
C: To ensure a complete seal thus helping in retention of a denture
Answer: C: To ensure a complete seal thus helping in retention of a denture 
Explanation: None