To explain the photoelectric effect, albert einstein linked the photoelectric effect to an idea from which scientist?

To explain black body radiation Max Planck describes light as discrete energy packets called photons. The energy of each photon is directly proportional to the frequency of light.  

E = hν, where E is the energy of light, h is Planck’s constant and ν is frequency of light. Einstein used Max Planck theory of quantization of light to explain photoelectric effect.  

answer; economic order quantity;

not clear