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': 'Retruded tongue position in an edentulous patient results in \nSelect and explain. \nA. Good peripheral seal, B. Over extended impression, C. Under extended impression, D. Increased stability of lower denture', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]