[单选题]
How can tobacco smoke ca8n8g.qtkk*fauejn ,j sv0p; /use breathing difficulties in smr ;8x dr/ke f5nkyar,vze4)p6okers?
A. It reduces the amount of mucus in the lungs.
B. It decreases the concentration of carbon monoxide in the blood.
C. It leads to an increase in the surface area of the lungs.
D. It increases the size of the alveoli.