Hint: The more free electrons are existing in a metal, the higher its conductivity. Relatively, silver has excellent electrical conductivity. Since silver is notably more expensive than copper, copper gets its application in all household instruments and circuits. Electrons' electric charge is implemented to the material at particular points; the electrons begin to move and support electricity to pass through it.
Complete step-by-step solution: Each material is varied and has its features and properties. Some materials have electrically energized particles identified as electrons. The capacity of the material to pass electricity by it is recognized as conductivity. If we differentiate two types of material and the first one provides a better electricity flow through it, then that material is stated to be a good conductor. An electrical conductor permits the electric charges to pass through them quickly. Such materials offer less resistance to the charge flow. Conducting materials allow simple charge transfer because of the free motion of electrons through them. A conductor always provides the mobility of electrons and ions in them. The electric field inside the conductor is zero, allowing electrons to move within them. The charge density concerning a conductor is zero. Free charges exist on the surface of the conductor only. All positions of a conductor are at equal potential. Most conducting substances used for practical purposes are metals. For example, the wire around our house seemingly uses copper wires as conducting materials. The electric connections have metal in them, and the internal device of our electric irons also utilizes metals as their conducting element because metals have many free electrons and support mobility. Some of the excellent metal conductors are Silver, Copper, and Gold. Option (a) is correct.
Note:Materials that have significant mobility of electrons are identified as conductors, and materials with smaller mobility of electrons are introduced as insulators. Many metals are excellent conductors of electricity. This is the idea why appliance parts that need to cross electricity are formed of metals. The plastic covering that encloses an electrical conductor is known as insulators. It stops us from getting an electric shock.