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: Radiology
[{'content': 'Premature filling of veins on cerebral angiography is a feature of \nSelect and explain. \nA. Trauma, B. Brain tumour, C. Aeriovenous malformation, D. Aerial occlusion', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .', 'role': 'assistant'}]