Subject :NSO Class : Class 9

Two satellites S_{1} and S_{2} revolve around a planet in coplanar circular orbits in the same sense. Their periods of revolution are 1 h and 8 h respectively. The radius of the orbit of S_{1} is 10^{4} km. When S_{2} is closest to S_{1}, then the speed of S_{2} relative to S_{1} will be

Aπ × 10^{4} km h^{-1}

B2π × 10^{4} km h^{-1}

C1 × 10^{4} km h^{-1}

D2 × 10^{4} km h^{-1}

could anyone give me a detailed solution for this?