This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Drugs, Subject name: Medicine
Aldose reductase inhibitor drugs are useful in? 
Select and explain. 
A. Cataract, B. Diabetes mellitus, C. Hereditary' fructose intolerance, D. Essential fructosuria
B: Diabetes mellitus
Answer: B: Diabetes mellitus 
Explanation: Ans. is 'b' i.e.. Diabetes mellitus o Aldose reductase catalyzes the NADPH-dependent conversion of glucose to sorbitol, the first step in polyol pathway of glucose metabolism.o Aldose reductase inhibitors are a class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes mellitus.o Examples of aldose reductase inhibitors include:Tolrestat (withdrawn from market)A pa l res tatRanirestatFidarestat