In the Years After Newton Published His Laws of Motion

Multiple Choice

In the years after Newton published his laws of motion, it was found that the observed positions of the planet Uranus did not match the predictions of Newton's theory. The reason for this turned out to be the

A) perturbing effects of Jupiter and Saturn, whose masses at that time were not accurately known.
B) perturbing effect of Neptune, which at that time had not yet been discovered.
C) perturbing effect of Pluto, which at that time had not yet been discovered.
D) weakening of gravity with increasing distance from the Sun.