Which of the Following Would Need to Be True for Kepler's

Multiple Choice

Which of the following would need to be true for Kepler's 3rd Law to apply to an extrasolar planetary system?

A) the parent star would have to have the same mass as the Sun
B) it would need to contain the same number of planets as our own solar system
C) the parent star would have to have the same mass as the Sun or higher
D) it would need to contain a planet that has the same mass as the Earth