The correct answer to the question which is stated above is letter c. Nerve net.
<span>Echinoderms, like sea stars, have a Nerve Net nervous system.
>></span><span>Nerve nets are found in members of the </span>Cnidaria<span>, </span>Ctenophora<span>, and </span>Echinodermata phyla<span>, which are found in </span>marine<span> environments. </span>