Sponges
a) have larvae which are motile and move via the motion of cilia
b) are the simplest diploblastic animals
c) have a nerve net but not a central nervous system
d) have feeding cells called dinoflagellates

Have larvae which are motile and move via the motion of cilia. (Ans. A)

Explanation:

Sponges: They are belongs to porifera phylum and defined as the simplest species. In sponge for particular function they are containing specialized cells, and they lack true tissues. All sponges are marine or aquatic in nature.

Sponge lives in contact with water because it helps them to excretion, gas exchange, and feeding. They can filter out the food, eliminate waste, and absorb dissolved oxygen with the help of body structure of sponge is dedicated to moving water.

Sponges produce motile larvae through the process of sexual reproduction, and move with the motion of cilia or budding formation through the process of asexual reproduction.