What area of research did brahe assign to kepler, which led to the development of his laws of planetary motion?

Answer;

D.) the retrograde motion of Mars

Explanation;Tycho Brahe established an observatory on an island given to him by  the king of Denmark where he spent 20 years recording the most precise astronomical observations the Western world had ever seen.Brahe was less competent in constructing models that would substantiate or explain his observations, so he hired Kepler. However, Brahe feared that Kepler would surpass him as the best astronomer of his day. Therefore, Brahe restricted Kepler's access to his research and assigned Kepler to investigate the orbital path of Mars.After his death, Kepler stole Brahe's research and used it together with his own work to formulate the correct model of the solar system and develop the three laws of planetary motion.