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': 'The most pre -dominant type of polio virus during \nSelect and explain. \nA. Type I, B. Type II, C. Type III, D. Combined infection of II & III', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]