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 ossifies by: March 2013 (b, f) \nSelect and explain. \nA. 6 months, B. 12 months, C. 18 months, D. 24 months', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C i.e. 18 months Its pathological if anterior fontanelle fails to ossify by 24 months', 'role': 'assistant'}]