Which result would support the particle theory of light? a)increasing the intensity of the light causes electrons to be ejected. b)frequencies of light that fall below the frequency threshold of the metal do not eject electrons. c)there is a time gap between when light strikes the metal and when electrons are ejected.

This question is related to the emission of electrons when light shines on an metal. (Photoelectric effect)

With the classical theory, it was thought that increasing or decreasing the intensity of light would increase or decrease the kinetic energy of the electron.,

Another expected result was that time gap between when light strikes the metal and when electrons are ejected, would depend on the intensity of such light.

However, the experimental results were not consistent with the particle theory of light. So your answer is A. 

Later on this effect was correctly explained by Einstein based on Planck's findings.