This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Structure & Function of Proteins), Subject name: Biochemistry
[{'content': 'Keratin contains - \nSelect and explain. \nA. Arginine, B. Histidine, C. Lysine, D. All', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., All", 'role': 'assistant'}]