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': 'Eruption of Maxillary 1st molar occur at \nSelect and explain. \nA. 8-9 years, B. 6 years, C. 4 years, D. 15-16 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]