The correct answer is D. Interference of light.
The wave theory of light can explain the phenomenon of interference, which is the superposition of two or more waves to produce a new wave pattern. This can be observed in the double-slit experiment, where light waves pass through two slits and interfere with each other to produce an interference pattern on a screen.
The Compton effect is the scattering of a photon by an electron, resulting in a change in the wavelength of the photon. This can be explained by the particle nature of light, as the photon interacts with the electron as a particle.
The photoelectric effect is the emission of electrons from a metal surface when light is shone on it. This can be explained by the particle nature of light, as the light photons have enough energy to knock electrons out of the metal.
The black body spectrum is the distribution of energy emitted by a black body, which is an idealized object that absorbs all radiation that falls on it. This can be explained by the wave nature of light, as the light waves are absorbed and re-emitted by the atoms in the black body.