The Milky Way Has Both a Thin and Thick Disk

Multiple Choice

The Milky Way has both a thin and thick disk of stars.Which of the following statements about them is true?

A) The thin-disk stars are, on average, younger than the thick-disk stars.
B) Molecular clouds are found in the thick disk, but not the thin disk.
C) The thick disk is made up of stars that were stripped from small dwarf galaxies as they merged with the Milky Way.
D) The thick-disk stars may be older than disk stars that have higher upward velocities, because they have gravitationally interacted more with molecular clouds in the spiral arms.
E) All of these statements are true.