What is the explanation given by Einstein for the photoelectric effect?

I- Einstein suggested that light is made up of small energy quanta called photons.
II- The energy of light quanta is linked to their frequency according to Planck's formula.
III- Einstein suggested that the exchange of energy between light and matter occurs continuously.
IV- The mechanism of extraction of electrons from a metal can be imagined as a collision between photons and electrons.
a) Only I and II are correct.
b) Only II and IV are correct.
c) Only I, II, and IV are correct.
d) Only III and IV are correct.
e) All statements are correct.