Kepler's third law of motion relates the period of revolution of a planet to its average distance from the sun. The correct variables to understand Kepler's third law are:
period of revolution, distance to sun.
However, since this exact phrasing isn't in your options, the closest correct choice would be:
orbital velocity, distance to sun.
Kepler's third law states that the square of the orbital period (time taken for one complete orbit) is directly proportional to the cube of the semi-major axis of its orbit (average distance from the sun).