The Discovery of Eris ________

Multiple Choice

The discovery of Eris ________.

A) was not surprising, because other Kuiper belt objects approaching the size of Pluto had already been discovered
B) was surprising, since we thought we knew about all large objects in the solar system
C) was surprising, due to its "backwards" orbit around the Sun
D) was not surprising, because the existence of a massive "Planet X" had been predicted nearly a century ago