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
Minimum duration of exposure required to develop coal miner's pneumoconiosis is: 
Select and explain. 
A. 8 years, B. 12 years, C. 15 years, D. 18 years
B: 12 years
Answer: B: 12 years 
Explanation: 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.