Which of the following statements correctly describes the models put forth by ptolemy and copernicus to explain the universe? a. both of the models were easy to understand and thus were well received by the public almost instantly. b. through observations, both astronomers presented models where the earth remained stationary. c. the model developed by copernicus was simpler and had less inconsistencies than ptolemy’s model. d. the sun was in the center of ptolemy's model, but the earth was in the center of copernicus' model.