The correct option is
B Musca-complete metamorphosis
A.
Pheretima - Sexual dimorphism is the condition where two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. But in earthworm sexes are united.
B. Musca- The insect with such metamorphosis has four stages in the life history: egg, larva, pupa and adult. Development with complete metamorphosis is called holometabolous development.
C. Chamaeleon- Mimicry is when a predator mimics its prey in order to catch it. An example of this is the cuckoo bee, which lays its eggs in the nest of bumble bees, which they closely resemble and prey upon. Chamaeleon is insectivorous and can catch an insect about 20 cm, away by the eversible tongue. It is known for changing colour ( camouflage).
D. Taenia - Polymorphism, a discontinuous genetic variation resulting in the occurrence of several different forms or types of individuals among the members of a single species. There is generally a single tapeworm in one host, due to the inability of the host to support more worms in its intestine.
So, the correct answer is 'Musca- complete metamorphosis'.