This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and Health, Subject name: Social & Preventive Medicine
[{'content': 'In malaria control, insecticide used for insecticide treated bed nets (ITBN)- \nSelect and explain. \nA. Deltamethrin, B. Malathion, C. Lindone, D. Fenitrothion', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Deitamethrin o Insecticide Treated Bed Nets (ITBN) Programme (esp. deitamethrin) has resulted in significant decline in malaria incidence and APIAverage decline in anopheline mosquito density - 68%Average decline in cuicine mosquito density - 50%o Chemicals used in ITBN Programme : Synthetic pyretheroidsDeitamethrin : 2.5% in dosage of 25 mg/m2Cyfluthrin: 5% in dosage of 50 mg/m2Other insecticides used : Permethrin, Lambdacyhalothrin, Etofenprox, Cypermethrino Effectiveness of pyrethroids: For 6-12 months (Retreatment every 6 months)o Long-lasting insecticidal mosquito nets (LLINs) : Also use pyrethroid insecticides, and a chemical binder that allows the nets to be washed > 20 times, allowing use for > 3 years.", 'role': 'assistant'}]