Einstein explained photoelectric effect on the basis of Planck's quantum theory, where light travels in the form of small bundles of energy called photons. The energy of each photon is $h\nu$, where $\nu$ is the frequency of incident light and $h$ is Planck's constant. The number of photons in a beam of light determines the intensity of the incident light. A photon incident on a metal surface transfers its total energy $h\nu$ to a free electron in the metal. A part of this energy is used in ejecting the electron from the metal and is called its work function. The rest of the energy is carried by the ejected electron as its kinetic energy. Which of the following graphs shows the variation of photoelectric current I with the intensity of light ? (A) [Graph showing I decreasing linearly with Intensity] (B) [Graph showing I constant with Intensity] (C) [Graph showing I increasing linearly with Intensity] (D) [Graph showing I increasing non-linearly/saturating with Intensity]