Assertion :Kinetic energy of photo electrons emitted by a photosensitive surface depends upon the intensity of incident photon. Reason: The ejection of electrons from metallic surface is possible with frequency of incident photon below the threshold frequency.
A. Both assertion and reason are correct and reason is the correct explanation for assertion
B. Both assertion and reason are correct but reason is not the correct explanation for aseertion
C. Assertion is correct but reason is incorrect
D. Both assertion and reason are incorrect"