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': '1st evidence of calcification of Upper central incisor is seen in \nSelect and explain. \nA. 3-4 months, B. 6-7 months, C. 8-9 months, D. 1-2 months', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]