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': 'At the physiological pH the DNA molecules are : \nSelect and explain. \nA. Positively charged, B. Negatively charged., C. Neutral., D. Amphipathic', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Negatively ChargedDNA molecules are negatively chargedQ, this is evident as it is stained by a cationic dye (Methylene blue).', 'role': 'assistant'}]