UPSC 2016 CDS II English Paper

SI: Don’t you think that the housefly is a nuisance ?
S6 : When you see a fly rubbing its legs together, it is just cleaning itself, and scraping off some of the material that has gathered there.
P : For ages that’s what man considered the fly to be — just a nuisance.
Q : It was discovered that these flies carried disease germs that cause the death of millions of people every year.
R : But now we know that the innocent looking housefly is one of man’s worst enemies.
S : It makes an irritating buzzing sound; it annoys you when it crawls on your skin; and so on.
The proper sequence should be