How did Kepler build upon the foundation established by Copernicus?

How did Kepler build upon the foundation established by Copernicus?
 
  a. Kepler used data to derive laws of planetary motion that confirmed Copernicus's heliocentric theory, but that showed the orbits were elliptical.
  b. Kepler observed the heavens and proved that planetary motion was circular around the sun.
  c. Kepler used magic to prove that the earth moved in a manner based on geometric figures, trying to bring harmony of the human soul into alignment with the universe.
  d. Kepler demonstrated that the motion of the planets is steady and unchanging.
  e. Kepler discovered the three laws of thermodynamics.