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': 'A child has 12 permanent and 12 deciduous teeth, what is his age: \nSelect and explain. \nA. 8 ½ years, B. 11 ½ years, C. 4 ½ years, D. 13 ½ years', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]