Correct option: (b)

Explanation:

Millipede is myriapod, silver fish is insecta and sea anemone is diploblastic. Duck bill platypus is a small semiaquatic oviparous mammal.

Ornithorhynchus anatinus, the Duckbill platypus, is a unique mammal native to Queensland, New South Wales, Victoria, South Australia, and Tasmania. This animal is about the size of a house cat and is covered by thick waterproof hair. It has a beak like a duck, webbed forelimbs for swimming, clawed hind feet for aid in burrowing, a common opening for the reproductive, excretory and digestive systems, and a broad, flat tail. In addition, the males have a single spur on each hind ankle that contains venom, and the females lay eggs.