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': 'Gas responsible for Bhopal Gas tragedy was: \nSelect and explain. \nA. Methyl isocyanate, B. Potassium isocyanate, C. Sodium isocyanate, D. Ethyl isocyanate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Methyl isocyanate', 'role': 'assistant'}]