Read the following article and answer the question by choosing from the options.

There was a rustic charm that I immediately fell in love with . Mosquito nets hangs above every bed , and there 's something very romantic about having them draped around you as you sleep . I never felt a mosquito while I was there , but I used the nets anyway .

How do mosquito nets keep out mosquitoes ?
Available choices:
 A). It is like a chemical aura;
 B). It is a mask that hides me away;
 C). It is so thin , it confuses the mosquitoes;
 D). None of the above choices .;...A:
D).