Which of the following are main types of energy?

Kinetic, potential, and thermal energy are indeed the main types of energy commonly discussed in physics. Kinetic energy refers to the energy of an object in motion, and it depends on the mass and velocity of that object. Potential energy is stored energy based on an object's position or configuration, such as gravitational potential energy for an object raised above the ground or elastic potential energy in a compressed spring. Thermal energy is associated with the temperature of an object and relates to the motion of particles within a substance; as temperature increases, so does the thermal energy due to increased particle movement.

The other options introduce different categorizations of energy but do not encompass the fundamental types recognized in classical mechanics. While mechanical energy is a valid concept that includes both kinetic and potential energy, it is not a distinct primary type on its own. Gravitational and magnetic energies can also be considered as forces acting on objects, but they do not define the primary energy types. Likewise, static and radiant energies are not categorized with the foundational definitions typically accepted in physics for basic understanding. Chemical energy is a significant type of energy related to chemical reactions, but it does not cover the broad spectrum of energy types outlined in the correct answer.