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: Microbiology
[{'content': 'Cell-Fraction derived vaccine is - \nSelect and explain. \nA. Hepatitis-B, B. Measles, C. Mumps, D. Rubella', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Hepatitis B", 'role': 'assistant'}]