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': 'Biopsy in PAN shows: \nSelect and explain. \nA. Necrotizing aeritis, B. Atrophy, C. Granulomatous lesion, D. Ring lesion', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Necrotizing aeritis): PAN is characterized by necrotizing vasculitis of small and medium sized muscular aeries. The vascular lesion in PAN is necrotizing inflammation of small and medium sized muscular aeries.', 'role': 'assistant'}]