Correct Option: C

The rotating machine should be protected against major and minor insulation. Major insulation is the insulation between the winding and minor insulation means inter-turn insulation. The major insulation is determined by line to ground voltage across the terminal of the machine whereas minor insulation is determined by the rate of rise of voltage. Hence to protect the rotating machine against surges requires limiting the surge voltage magnitude at the machine terminals and sloping the wave front of the incoming surge. To protect the major insulation, a special lighting arrester and to protect the minor insulation a capacitor are required and connected as depicted in the given figure.