The correct option is
D CoelenterataNematocysts are specialized stinging cells specific to
Coelenterates that act as organs of offense and defense. They are cell organelles which are found in specialized cells called as cnidocytes or cnidoblasts, which are modified epidermal interstitial cells.
Nematocysts may occur scattered throughout the body surface, except the basal disc. They are abundant on the tentacles and hypostome.Therefore, the correct answer is option B.