The correct option is C Locomotion
Ctenophora is a phylum of invertebrate animals that live in marine waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are the largest animals that swim by means of cilia. The outer surface of these animals bears usually eight comb rows, called swimming-plates or comb-plates, which are used for swimming. The rows are oriented to run from the oral pole to the aboral pole and are spaced more or less evenly around the body.