This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Entomology, Subject name: Social & Preventive Medicine
[{'content': 'Organophosphate insecticides are all except: \nSelect and explain. \nA. Dieldrin, B. Fenthion, C. Diazinon, D. Chlorpyrifos', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Organo phosphorous insecticides Malathion Parathion Fenthion Diazion Fenitrothion Chlorpyrifos Dioxathion Chlohion Organo chlorine insecticides DDT BHC (HCH) Lindane Dieldrin Carbamate insecticides Carbaryl Propoxur', 'role': 'assistant'}]