This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharyngeal Arches, Subject name: Anatomy
[{'content': 'Posterior fontanelle fuses at ? \nSelect and explain. \nA. 2-3 months, B. 12 months, C. 18-24 months, D. 36 months', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 2-3 months -fusion of posterior fontanelle. 18-24 months - fusion of anterior fontanelle.', 'role': 'assistant'}]