Incorrect statements
Statement c: Polyp produce medusae sexually and medusae form the polyp asexually (eg: Obelia).
Elaboration :
Obelia (Sea fur) belongs to the class Hydrozoa of the kingdom Cnidaria that shows polyp (cylindrical) as well as medusa (umbrella-shaped) form in its life cycle.
Statement d: Metagenesis is seen in jellyfish.
Elaboration :
Cnidarians, which exhibit both the types of body forms, polyp (cylindrical) and medusa (umbrella-shaped), exhibit metagenesis. Aurelia (jelly-fish) only shows umbrella-shaped (medusa) form and therefore, does not exhibit metagenesis. Hence, statement ‘d’ is incorrect.
Final answer
d. c,d