Direction: 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.

When corn is (A) nibbled by caterpillars, for example, the plant (B) lures a chemical (C) distress signal that (D) emits parasitic wasps to (E) exterminate the caterpillars.