C

Step 1: Johannes Kepler was a key figure in the field of astronomy and is best known for his three fundamental laws of planetary motion.
Step 2: These laws describe how planets move around the Sun in elliptical orbits, with varying speed depending on their distance from the Sun.
Step 3: The first law (the law of ellipses) states that planets move in elliptical orbits with the Sun at one of the foci.
Step 4: The second law (the law of equal areas) states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
Step 5: The third law (the law of harmonies) relates the square of the orbital period of a planet to the cube of the semi-major axis of its orbit.
Thus, the correct answer is C: Laws of planetary motion.