The following sentences form a paragraph. The sentences are numbered as P, Q, R, S and T. These sentences are not given in their proper order. Read the sentences and choose the right option out of five alternatives that correctly arranges the sentences in the correct sequence.

16.  So inspite of several requests of his roommates to stop singing at least in the morning, he has continued his unmusical practice.
17.  This indifferent attitude of Rafiklal is slowly building up bitterness among those roommates.
18.  Every morning Rafiklaal starts singing but in a very cacophonous manner.
19.  This unmelodious singing always irritates his roommates but he contemplates himself as a great singer.
20.  Rafiklal is also aware that this accumulated antipathy can anytime translate into a big pandemonium.