In a Distant Galaxy, a Planet Orbits Its Sun at a Distance

In a distant galaxy, a planet orbits its sun at a distance of 1.8 *10¹² m with a period of 10⁸ s. A second planet orbits the same sun at a distance of 9 *10¹¹ m. What is the period of the second planet?

A) 5 * 10⁷ s
B) 2 * 10⁸ s
C) 0.35 * 10⁸ s
D) 2.8 * 10⁸ s
E) 5 * 10⁸ s