The Studies of Light Emitted by Hot Objects (Max Planck)

The studies of light emitted by hot objects (Max Planck) and the photoelectric effect (Albert Einstein) revolutionized physics because they revealed ________

A) that energy is quantized.
B) that light intensity does not affect the number of electrons ejected from a metal.
C) that atomic spectra are due to the quantized transitions of electrons.
D) that blackbody radiation is continuous.
E) that atomic spectra are continuous.