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': 'Muscle biopsy in PAN shows - \nSelect and explain. \nA. Necrotising arteritis, B. Atrophy, C. Granulomatous lesions, D. Ring lesions', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]