Option C
Explanation:
Crabs, lobsters and crayfish belong to the taxon Crustacean while scorpion is an Arachnid.
Crustacean (Arthropods) are aquatic & terrestrial free living species whose body is composed of segment and mainly comprise of three main parts i.e head , thorax and abdomen. Â
They have a hard layer of exoskeleton that protects their body from external damage. Â
Arachnids (arthropods) are aquatic and fresh water species with external skeleton, and joined appendages. They also have covering of exoskeleton