Fact 1: Echinoderms have a unique water vascular system with tube feet. Fact 2: Each starfish arm is lined with tube feet. Given the two facts above, what is an example of an echinoderm?

Pick from:
[i] a fish;
[ii] eel;
[iii] starfish;
[iv] parasites;
[v] ferns;
[vi] shark;
[vii] fertile;
[viii] algae;
The answer is:
[iii]