Which type of heat transfer involves radiant heat?

The correct answer involves the concept of radiant heat transfer, which is the process by which thermal energy is emitted as electromagnetic waves, primarily in the infrared spectrum. This transfer occurs without the need for a medium; hence, it can happen even in a vacuum.

When a hot body emits heat, the energy travels through space until it reaches a cooler body, resulting in a temperature increase for the cooler body. This is why sunlight can warm the Earth's surface despite the vacuum of space.

In this instance, option C accurately captures the essence of radiant heat transfer, illustrating that heat moves from a hot body to a cold one through radiation. This distinguishes it from other types of heat transfer, such as conduction or convection, which require physical contact or fluid movement, respectively.