Why Do the Terrestrial Planets Have a Much Higher Fraction

Multiple Choice

Why do the terrestrial planets have a much higher fraction of their mass in heavy chemical elements than the giant planets?

A) Terrestrial planets are low in mass and high in temperature, thus their lighter chemical elements eventually escaped to the outer reaches of the Solar System.
B) The heavier elements in the forming solar nebula sank to the center of the Solar System, thus the inner terrestrial planets formed mostly from heavy chemical elements.
C) The giant planets were more massive than terrestrial planets, and the giant planets preferentially pulled the lighter elements from the inner to the outer Solar System.
D) Terrestrial planets formed much earlier than giant planets, before the hydrogen and helium had a chance to cool and condense onto them.
E) Terrestrial planets are colder and thus more massive chemical elements condensed on them than on the giant planets.