Which of the following scientist had proven that every planet has an elongated path?

Kepler through his 'planetary law of motion' proved that every planet has an elongated path. Kepler had believed in the Copernican model of the solar system, which called for circular orbits, but he could not reconcile Brahe's highly precise observations with a circular fit to Mars' orbit – Mars coincidentally having the highest eccentricity of all planets except Mercury.