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': 'Yellow fever aedes agypti index should be ? \nSelect and explain. \nA. <1%, B. < 5%, C. <10%, D. < 20%', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., < 1%", 'role': 'assistant'}]