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': 'The following is not a Nerve gas - \nSelect and explain. \nA. Sarin, B. Tabun, C. Soman, D. Pyrolan', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sarin, Soman, and Tabun are organophosphate nerve agents while Pyrolan is a carbamate.', 'role': 'assistant'}]