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': "Minimum duration of exposure required to develop coal miner's pneumoconiosis is: \nSelect and explain. \nA. 8 years, B. 12 years, C. 15 years, D. 18 years", 'role': 'user'}, {'content': "Answer: B \nExplanation: Coal miner's pneumoconiosis or anthracosis is caused by exposure to coal dust. Exposure of around 12 years may be required before symptomatic disease develops. Ref: Park 21st edition page: 747.", 'role': 'assistant'}]