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': 'In SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis) proteins are separated on basis of: \nSelect and explain. \nA. Mass, B. Charge, C. Density, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Mass', 'role': 'assistant'}]