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: Pathology
[{'content': 'All are causes of granular contracted kidneys,except- \nSelect and explain. \nA. Benign nephrosclerosis, B. Diabetes mellitus, C. Chronic PN, D. Chronic GN', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]