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': 'Smoke index is used for- \nSelect and explain. \nA. Air pollution, B. Soundpollution, C. Excreta, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Monitoring of air pollution\nMonitoring of air pollution is done by : -\n\nSulphur dioxide.\nGritt and dust measurement.\nCo-efficient of haze.\nAir pollution index.\nSmoke or soiling index', 'role': 'assistant'}]