Answer: The correct answer is an electrical insulator.
Explanation:
Insulator : It is a material which resists the flow of electrons. It has high resistance in comparison to the conductor.
Conductor: It is a material which allows the flow of electrons. It has low resistance in comparison to the conductor.
Battery is a source of electrical energy. It forces the electrons to flow. The rate of flow of electrons constitutes the current.
In the given problem, an electrical insulator is not needed for a charge to flow through a conducting wire.
To design the circuit and to make a current flow in the circuit, a battery, a wire connected in a complete loop and a source of electrical energy are needed.
Therefore, the correct option is (C).
