Magnetism

The concept that metallic conductors contain a large number of free electrons was proposed by Drude and Lorentz. Their free electron theory of conductivity suggests that metals have free electrons that can move within the conductor, which is responsible for electrical conductivity. This theory laid the groundwork for understanding the behavior of electricity in metals.
Oersted is known for discovering the relationship between electricity and magnetism.
Ohm formulated Ohm's law, which relates voltage, current, and resistance.
Kirchhoff is known for Kirchhoff’s laws, which are fundamental for circuit analysis.

The correct option is (D): Drude and Lorentz