Which statement best explains why extremely high temperatures are required to initiate hydrogen fusion in a laboratory reactor?
(a) At high temperature, the plasma pressure becomes so large that it forces protons together, enabling fusion.
(b) High temperature strips away electrons from hydrogen atoms; without electrons, protons can merge more readily.
(c) At high temperature, the average kinetic energy of protons is sufficient to overcome their electrostatic repulsion, allowing the strong nuclear force to bind them.
(d) High temperature weakens the Coulomb force between protons, so they can approach close enough to fuse.