In Copernicus's Theory, Retrograde Planetary Motion Is Explained as

Multiple Choice

In Copernicus's theory, retrograde planetary motion is explained as

A) the backward part of the planet's loop- the- loop orbits around Earth.
B) due to the back- and- forth or "oscillatory" motion that planets make as they move along their circular orbits around Earth.
C) due to the natural wandering of the celestial sphere of background stars.
D) a result of Earth's motion: as Earth passes another planet, that planet appears to move backward as seen against the background stars.
E) Actually he didn't have an explanation for this.