The correct option is B Crinoidea
Feather stars are a group of crinoids. Crinoids are the group of organisms with multiple arms. These organisms belongs to the order Crinoidea. They are crinoids without stalks. They are different from sea lilies which are stalked crinoids. Feather stars are benthic animals. They can freely swim when compared to the sea lilies which are fixed organisms.
Thus, the correct answer is option B.