**Explanation:**

The correct answer is **c) Quantum Theory**.

The radiation emitted by black bodies is explained by **Quantum Theory**.

Black bodies are idealized objects that absorb all incident radiation and emit radiation at all wavelengths and intensities. According to classical physics, a black body should emit an infinite amount of energy, which is known as the "ultraviolet catastrophe". However, this prediction contradicts experimental observations.

Quantum theory, on the other hand, provides an explanation for the radiation emitted by black bodies. It suggests that the energy emitted by a black body is quantized, meaning it can only take on certain discrete values. This is in contrast to classical physics, which assumes that energy can take on any value.

**Planck's Radiation Law:**

Max Planck, in 1900, proposed a mathematical formula that accurately described the observed spectrum of radiation emitted by a black body. This formula, known as Planck's radiation law, is derived from the principles of quantum theory.

Planck's radiation law states that the energy emitted by a black body is proportional to the frequency of the radiation and is given by the equation:

E = h * f

where E is the energy, h is Planck's constant, and f is the frequency of the radiation.

This equation implies that the energy emitted by a black body is quantized in discrete packets (quanta) of energy, where the energy of each quantum is directly proportional to the frequency of the radiation.

**Conclusion:**

In conclusion, the radiation emitted by black bodies is explained by **Quantum Theory**. Quantum theory provides a framework for understanding the quantized nature of energy and accurately describes the observed spectrum of radiation emitted by black bodies, as explained by Planck's radiation law.