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: Pediatrics
[{'content': 'Anterior fontanelle closes at ? \nSelect and explain. \nA. 2-3 months, B. 4-7 months, C. 9-12 months, D. 18-24 months', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is `d' i.e., 18-24 months", 'role': 'assistant'}]