This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Occupational Health, Subject name: Social & Preventive Medicine
Paicle size which is inhaled by lung and causes damage is: 
Select and explain. 
A. <0.5 micron, B. 0.5 - 3 micron, C. 3-5 micron, D. 5-10 micron
B: 0.5 - 3 micron
Answer: B: 0.5 - 3 micron 
Explanation: Paicle size and lung damage: Paicle size Remarks <0.5 micron Brownian motion 0.5 - 3 micron Most dangerous paicle size 3-5 micron Trapped by mid - respiratory tract 5-10 micron Trapped by upper - respiratory tract > 10 micron Settle by gravity