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: Social & Preventive Medicine
[{'content': 'False about vaccines is - \nSelect and explain. \nA. Thiomersal is preservative in DPT vaccine, B. Kanamycin is preservative in measles, C. Magnesium chloride stabilizer used in OPV, D. Neomycin is a preservative in BCG vaccine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]