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': 'At what age does the first tooth erupt in the oral cavity? \nSelect and explain. \nA. 6 months, B. 9 months, C. 6 weeks, D. 7 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]