Because of the Ages of Globular Clusters in the Milky

Because of the ages of globular clusters in the Milky Way, we think our galaxy's early formation history was characterized by

A) one single cloud of gas gently collapsing and star formation proceeding slowly within it.
B) one single cloud of gas that rapidly collapsed and turned most of its gas into stars.
C) the merging of protogalactic fragments that stimulated a high rate of star formation.
D) the merging of globular clusters that were already fully-formed.
E) the merging of two galaxies, each about half as massive as the Milky Way is today.