Why Did the Discovery of a 17 Earth Mass Terrestrial

Multiple Choice

Why did the discovery of a 17 Earth mass terrestrial exoplanet surprise astronomers?

A) It implies that Earth lost a great deal of mass in the early solar system.
B) Such a large planetary mass was thought to be gravitationally unstable.
C) Models had predicted that the formation of such a large rocky core requires a protoplanetary disk many times larger than that of the solar system.
D) Models had predicted that a rocky protoplanet of such a mass would attract enough hydrogen to form a gas giant.