This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Assessment of Growth, Subject name: Pediatrics
[{'content': 'At what age do first permanent teeth appear? \nSelect and explain. \nA. 5 years, B. 6 years, C. 7 years, D. 8 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) 6 yearsREF: Nelson 18th Ed Ch 8Repeat 2013 Session 2', 'role': 'assistant'}]