The correct option is A Hydranths
A hydranth is a feeding zooid in a hydroid colony having an oral opening surrounded by tentacles. They contain stomach regions. The individual Hydranth is called as gastrozooids.
A medusa is a body form of certain cnidarians which constitute the free-swimming sexual stage of the organism.
Blastostyles are the central rod-like portion of a gonangium, upon which buds that develop into medusae are formed.
Therefore, the correct answer is option B.