This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'Which of the following is the most common cause of congenital hydrocephalus? NOT RELATED-MEDICINE \nSelect and explain. \nA. Craniosynostosis, B. Intra uterine meningitis, C. Aqueductal stenosis, D. Vein of Galen malformation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .', 'role': 'assistant'}]