What evidence exists that electrons are found in quantized energy levels?

A) Line spectra of all the primary colors
B) Line spectra with a limited number of lines of color
C) Continuous wave spectra from photons
D) There is no evidence for this.

Line spectra with a limited number of lines of color provide evidence for quantized energy levels. When electrons in an atom transition between these levels, they emit or absorb photons of specific energies, resulting in discrete spectral lines rather than a continuous spectrum. This phenomenon cannot be explained without the concept of quantization.