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': 'Following are polar amino acids, except: \nSelect and explain. \nA. Isoleucine, B. Serine, C. Arginine, D. Histidine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Isoleucine', 'role': 'assistant'}]