Answer:
A. Polyp
Explanation:
Hydrozoa is one of the four classes of phylum Cnidaria. Hydrozoans exhibit alternation between polyp and medusa. Polyps are the dominant, specialized and more conspicuous in hydrozoans than medusae.
For example, in Obelia, sexually reproducing minute medusae develop on the tips of polyps and have a diameter of less than one centimeter.
