How Do Galaxies Evolve on the Hubble Tuning-Fork Classification Scheme

Multiple Choice

How do galaxies evolve on the Hubble tuning-fork classification scheme and what is the evolutionary significance of this diagram, shown in Figure 17-15 of the text?

A) About three-quarters of galaxies do not evolve, but others can change their position. Usually, spiral galaxies merge to form ellipticals.
B) The "young" irregular and lenticular galaxies in the center of the tuning fork evolve to either elliptical galaxies if the material is metal-poor or spiral galaxies if the material is metal-rich.
C) Stars slowly die and the spiral arms slowly spin up and tighten to transform spiral galaxies into elliptical galaxies.
D) Elliptical galaxies slowly condense and spin up to form spiral galaxies, the increasing stellar collisions forming the interstellar material in the spiral arms.