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': 'SDS - PAGE Separater proteins based on: \nSelect and explain. \nA. Charge, B. Solubiliy, C. Size, D. Polarity', 'role': 'user'}, {'content': 'Answer: C \nExplanation: SDS - PAGE imparts equal negative charges, thus nullifying the effect of charge.\nIt separates proteins purely on the basis of size (molecular weight).', 'role': 'assistant'}]