In which of the following does transfer of heat through electromagnetic waves occur? 

Here, we'll go on by describing each of the several heat transfer procedures that are specified in the problem's available alternatives (i.e., conduction, convection and radiation). The reasons of their heat transmission will then be noted.
Direct molecular collisions are used to transfer heat during conduction. Thermal energy will be transferred from an area with higher kinetic energy to one with lower kinetic energy. Collisions between faster and slower moving particles are possible. The slower-moving particles will therefore cause an increase in kinetic energy. Heat is transferred most frequently by conduction, which involves physical contact. Examples include placing metal in a flame or rubbing your palm on a glass.

The thermal energy is carried along if a gas, like air or liquid, is heated and then travels away from the source. Convection is the name given to this method of heat transmission. Over a heated surface, the fluid is growing, expanding, and becoming less dense.
When heat energy is provided, molecules at the molecular level expand. The volume of the fluid must grow by the same amount as the temperature of the supplied fluid mass. Displacement is caused by the fluid action. As the hot air that follows rises, it pushes away denser, colder air.

Emissions of electromagnetic waves result in thermal radiation. These waves drain the energy from the emitting body. In a vacuum or through a clear material, radiation occurs (solid or fluid). The immediate result of spontaneous movements between atoms and molecules in matter is thermal radiation. Electromagnetic radiation is released as a result of the charged protons and electrons moving.
Therefore, radiation is the name given to the process of heat transmission by electromagnetic waves.

Hence, the correct answer is option C.