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': 'The presence of which of the following factors in\nviruses makes protective vaccines a possibility? \nSelect and explain. \nA. Enzymes, B. Protein coat, C. Polysaccharide, D. Lipids', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]