This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pathology
[{'content': 'Which vasculitis affects both aerial and venous system \nSelect and explain. \nA. Wegeners granulomatosus, B. PAN, C. Behcets disease, D. Kawsaki disease', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Small vessel vasculitis affects aerioles, capillaries and venules. Of the options given, the only small vessel vasculitis is Wegener granulomatosis. (Ref: Robbins 8/e p511)', 'role': 'assistant'}]