Directions : This question consists of a sentence, parts of which have been jumbled. These parts have been labelled as P, Q, R and S. Given below each sentence are four sequences, namely (a), (b), (c) and (d). You are required to re-arrange the jumbled parts of the sentence and mark your response accordingly. 

grass comes from (P) / the smell of fresh cut (Q) / the chemicals plants (R) / release when in distress (S)