Ptolemy, an astronomer who lived during the second century CE, created a deeply complex model to describe the motion of the planets, a category he thought included the moon and the sun. He believed that all these celestial objects rotated around Earth, which he took to be the center of the universe. This is called a "geocentric model." In the 1400s, Copernicus became dissatisfied with the complexity and apparent arbitrariness of Ptolemy's model as an explanation of planetary motion. He began to ask what the planetary motions would look like from another vantage point in space, such as the sun. Pursuing this hypothesis led Copernicus to a system that describes planetary motion as centered around the sun. This is the "heliocentric model," a hypothesis whose implications have been repeatedly tested.

Which of the following are accurate descriptions of the development of Copernicus's hypothesis?
Check all that apply.

A. Copernicus's hypothesis was wrong because it had no foundation in established religious beliefs.
B. Copernicus's hypothesis was wrong because Ptolemy's hypothesis was widely held.
C. Copernicus developed his hypothesis in response to Ptolemy's hypothesis about planetary rotation, a hypothesis he found unsatisfying.
D. Copernicus saw an unsatisfying explanation and formulated a testable way to understand the motion of the planets.
E. Copernicus's hypothesis was a tentative explanation for the motion of the planets.