Answer:
c. the beating of the flagella of collar cells, forming a current; food is absorbed by collar cells.
Step-by-step explanation:
Sponges contains the unique feeding system that should be with the animals. Rather of mouths they have the tiny pores that we called as the ostia displayed on the outer walls via water is drawn. Here cells in the sponge walls strainer the food from the water because the water is pumped via the body and the little mouth
So as per the given options, the option c is correct as the collar cells would create the current and the food should be absorbed by the collar cells