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: Surgery
[{'content': 'Premature filling of veins is a manifestation incerebral angiography of - \nSelect and explain. \nA. Trauma, B. Brain tumour, C. Arteriovenous malformation, D. Arterial occlusion', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In A.V. malformation there is rapid blood flow in veins.', 'role': 'assistant'}]