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': 'Northern blot is used for the separation of - \nSelect and explain. \nA. mRNA, B. DNA, C. Protein, D. Protein DNA interaction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]