This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
All are causes of granular contracted kidneys, except- 
Select and explain. 
A. Benign nephrosclerosis, B. Diabetes mellitus, C. Chronic PN, D. Chronic GN
B: Diabetes mellitus
Answer: B: Diabetes mellitus 
Explanation: In benign nephrosclerosis, the kidneys will be reduced in size, and weight. The capsule is often adherent to the coical surface. The surface of the kidney is finely granular and shows V-shaped areas of scaring. In chronic pyelonephritis, the kidneys are small and contracted, showing an unequal reduction, which distinguishes it from other contracted kidneys. In chronic glomerulonephritis, the kidneys are small and contracted. The capsule is adherent to the coex and the coical surface is diffusely granular. on cut section, the coex is narrow and atrophic, while the medulla is unremarkable. From Textbook of pathology Harsh Mohan,6th edition pg no:687,682,674