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': 'If API>2, the vector is resistant to DDT, the malathion spray should be done every \nSelect and explain. \nA. 3 round of malathion every 3 months, B. 2 round or malathion every months, C. 1 -2 round of malathion every 3 months, D. One round of malathion every month', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]