This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'Xanthinurate is a product/intermediate metabolite of \nSelect and explain. \nA. Phenylalanine, B. Leucine, C. Tryptophan, D. Isoleucine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Conversion of tryptophan metabolite 3 hydroxy kynurenine to 2 hydroxy anthranilate is impaired in vitamin B6 deficiency? hence large amount of xanthinurate is formed.', 'role': 'assistant'}]