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': 'As compared to permanent tooth, root formation in primary tooth: \nSelect and explain. \nA. Take less time, B. Take more time, C. Same time, D. Is complete when tooth erupts in oral cavity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]