The correct answer is Mollusks, Echinoderms, Chordates, and Annelids.
This is basically how evolution works, at a certain point in the past,
there was a transitional organism that eventually developed into
roundworms and the other part of his species that was exposed to other
things evolved into other transitional organisms who evolved eventually
into these 4 groups.
Im not 100% sure but the best answer I can give is Prokaryotes because they came to be around the time oxygen did as well.
