In the sentence, certain words are in bold and numbered from A to E, which are the possible pairs to be interchanged.Choose the pair(s) of words which need to be interchanged to make the sentence grammatically correct and meaningful.

We think of (A) growth as the time of (B) blossom and (C) fresh new green (D) spring, but it is often the most (E) polluted time of year in western Europe.