The Period of a Planetary Orbit About a Star Is

The period of a planetary orbit about a star is 1.5 Earth years, whereas the average distance between the planet and the star is 2.0 AU (astronomical units) . A second planet is orbiting the star with a period of 12 Earth years. The orbital radius of the second planet is

A) 9.0 AU.
B) 16 AU.
C) 8.0 AU.
D) unknown; the orbital radius cannot be determined from the information given.