From the following list of observations, choose the one that most clearly supports the conclusion that electrons have wave properties. A) the emission spectrum of hydrogen
B) the photoelectric effect
C) the scattering of alpha particles by metal foil
D) diffraction
E) cathode "rays"

diffraction

Explanation:

Louis de Broglie in 1924 proposed the idea of wave particle duality. In his proposition, matter could exhibit wavelike properties.

Electrons are generally regarded as particles. Electrons may also display wavelike properties such as diffraction patterns. Generally, diffraction is regarded as a property of waves.

Hence, electron diffraction effect owes to the wavelike nature of of electrons when they are passed near matter.