Two satellites of earth, S, and S, are moving in the same orbit. The mass of S, is four times the mass of S. Which one of the following statements is true? (a) The potential energies of earth satellites in the two cases are equal. (b) S, and S, are moving with the same speed. (c) The kinetic energies of the two satellites are equal. (d) The time period of S, is four times that of S.