The correct answer is B. Parasite.
A parasite is an organism that lives on or in another organism (its host) and benefits by deriving nutrients at the host’s expense. Parasites can be animals, plants, fungi, or protists. They can be external parasites, living on the surface of the host, or internal parasites, living inside the host’s body.
Viruses are not considered to be living organisms because they do not have cells. They are made up of a protein coat and a nucleic acid core. Viruses can only replicate inside living cells. They do this by hijacking the cell’s machinery and using it to make more viruses.
Option A, Dependant, is incorrect because viruses are not dependent on other organisms for survival. They can replicate on their own, but they need to infect a host cell in order to do so.
Option C, Symbiotic, is incorrect because viruses are not beneficial to their hosts. They cause disease and can even kill their hosts.
Option D, Plebiscite, is incorrect because a plebiscite is a vote by the people on a particular issue. It has nothing to do with parasites or viruses.