The correct option is A Process of transforming a larva into an adult
Metamorphosis is the process of transformation from an immature form to an adult form in two or more distinct stages. metamorphosis generally takes place in insects or amphibians and some molluscs, crustaceans, cnidarians, echinoderms and tunicates.
A very good example of metamorphosis is changed that take place from tadpole to form a frog.
So, the correct answer is option A.