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: Medicine
[{'content': "All of the following are small vessels vasculitis, Except: \nSelect and explain. \nA. Classical PAN, B. Wegner's granulomatosis, C. HSP, D. Churg Strauss Syndrome", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Classical PAN): Classical PAN is a predominantly medium vessel vasculitis and not a small vessel vasculitis.', 'role': 'assistant'}]