The correct option is A Annelida
Annelids have tube-in-a-tube body plan. They have a segmented body. The identical segments each contain circular and longitudinal muscles. The outside of the worm is covered with small stiff bristles called as setae. Setae are made of chitin, and each of them is equipped with a tiny retractor muscle. Setae function to anchor the worm in its burrow, and also to help it crawl along. Therefore, the correct answer is option A.