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': 'The process of exfoliation of primary teeth is between \nSelect and explain. \nA. Seventh and eight years, B. Seventh and ninth years, C. Seventh and tenth years, D. Seventh and twelfth years', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]