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': 'Unilateral small smooth kidney is seen in - \nSelect and explain. \nA. Reflux nephropathy, B. Lobar infarction, C. Renal artery stenosis, D. Chronic glomerulonephritis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]