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': 'Ion exchange chromatography is based on \nSelect and explain. \nA. Size, B. Charge, C. Solubility, D. Polarity', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Charge", 'role': 'assistant'}]