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 developing coal minor pneumoconiasis is – 
Select and explain. 
A. 2–4 years, B. 4–6 years, C. 8–10 years, D. More than 10 years
D: More than 10 years
Answer: D: More than 10 years 
Explanation: Coal worker pneumoconiosis (Antracosis) 

There are two general phases in coal miners pneumoconiosis


The first phase : Simple pneumoconiosis : This is associates with only little ventilatory impairment but requires 12 years of work exposure for its development.
The second phase : Progressive massive fibrosis : This is associated with severe respiratory disability and takes much longer.