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': "Hanup's disease is associated with increased urinary excretion of: \nSelect and explain. \nA. Tryptophan, B. Ornithine, C. Glycine, D. Cystine", 'role': 'user'}, {'content': "Answer: A \nExplanation: Hanup's disease is characterized by low plasma levels of tryptophan and other neutral amino acids and their elevated urinary excretion", 'role': 'assistant'}]