The electric wires are made up of copper but we hardly see the copper wires directly as they are coated with PVC. Why they are needed to be covered with PVC? 

In general, metals are good conductors of heat and electricity. As copper is also a good conductor of electricity, it is used to make electric wires but if a person touches them directly, he/she can get a shock, To prevent such accidents, they are covered with polyvinyl chloride (PVC) coatings as PVC is a poor conductor and thus do not cause any shock.

Hence, the correct option is (C).