PLEASE HELP!!
Kepler's first law states that
A. the square of the orbital period of a planet is directly proportional to the cube of the semimajor axis of its orbit.
B. the square of the orbital period of a planet is indirectly proportional to the cube of the semimajor axis of its orbit.
C. planetary orbits are elliptical in shape.
D. planets remain at a constant distance from the Sun.