Step 1: Understanding the photoelectric effect.
In the photoelectric effect, the kinetic energy of the emitted photoelectrons is related to the intensity of incident radiation. However, the maximum kinetic energy of the photoelectrons does not depend on the intensity of the light, but rather on the frequency of the incident radiation. As the intensity increases, the number of emitted electrons increases, but the maximum kinetic energy remains constant.
Step 2: Conclusion.
Thus, the graph that shows a constant kinetic energy as intensity increases is the correct one, which corresponds to Graph C.