Two satellites of earth, $S_1$ and $S_2$, are moving in the same orbit. The mass of $S_1$ is four times the mass of $S_2$. Which one of the following statements is true?

1. A
   The time period of $S_1$ is four times that of $S_2$.
2. B
   The potential energies of the earth and satellite in the two cases are equal.
3. C
   $S_1$ and $S_2$ are moving at the same speed.
4. D
   The kinetic energies of the two satellites are equal.