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
[{'content': 'Post dam area serves mainly to: \nSelect and explain. \nA. Prevent ingress of food and saliva beneath denture base, B. Preventing Lifting away of denture during incising, C. Stabilize the denture, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]