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': 'According to International Health Regulations, there is no risk of spread of yellow fever if the Aedes aegypti index remains below: \nSelect and explain. \nA. 1%, B. 5%, C. 8%, D. 10%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 1%', 'role': 'assistant'}]