求教prep1-34

Hundreds of species of fish generate and discharge electric currents, in bursts or as steady electric fields around their bodies, using their power either to find and attack prey, to defend themselves, or also for communicating and navigating.

(A) either to find and attack prey, to defend themselves, or also for communicating and navigating

(B) either for finding and attacking prey, defend themselves, or for communication and navigation

(C) to find and attack prey, for defense, or communication and navigation

(D) for finding and attacking prey, to defend themselves, or also for communication and navigation

(E) to find and attack prey, to defend themselves, or to communicate and navigate

答案是C，我想选E，不明白是怎么平行的，请指点！

lz是不是看错答案了？我破解版的1-34答案是E啊？

汗。。。