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: Biochemistry
[{'content': 'Cataract in galactosemia is caused by accumulation of: \nSelect and explain. \nA. Sorbitol, B. Galactitol, C. Galactose, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Inability to metabolize galactose occurs in the galactosemia, which may be caused by inherited defects of galactokinase, uridyl transferase, or 4-epimerase, though deficiency of uridyl transferase is the best known. Galactose is a substrate for aldose reductase, forming galactitol, which accumulates in the lens of the eye, causing cataract. Ref: Harper 28th edition, chapter 21.', 'role': 'assistant'}]