lf Einstein’s photoelectric equation is represented by hf - W = Φ where h is Planck’s constant, f the frequency of incident radiation and W the work function of the material, what does the symbol Φ up stand for?

• A.Energy of the photons
• B.Maximum Kinetic energy of the ejected electrons
• C.Threshold frequency of the photons
• D.Stopping potential of the electrons
• E.Velocity of the electrons