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. 

Humboldt squid can (A) luminescence change the pigmentation and (B) rapidly patterns on their skin by (C) contracting and (D) relaxing their muscles, possibly to (E) communicate.