Which of the following is a common conductor?

A common conductor is a material that allows electric current to flow through it with minimal resistance. Copper is widely recognized as one of the best conductors of electricity due to its excellent electrical conductivity, durability, and resistance to corrosion. It is frequently used in electrical wiring, electronics, and various electrical applications to ensure efficient transmission of electrical energy.

In contrast, materials like rubber, plastic, and glass are typically insulators, meaning they do not conduct electricity well. They are used to prevent the flow of electricity, providing safety and protection in electrical systems. Thus, copper stands out in this context as the most effective and reliable conductor among the options presented.