What is the significance of the contrast between the plain exterior of the Oratory of Galla Placidia (Figs. 7-19, 7-20, and 7-21) and its highly decorated interior?

It symbolizes the transition from the real world into a supernatural realm.

It reflects the economic needs to limit the decorative programs of churches.

It shows Christianity’s adoption of Jewish themes.

It symbolizes Christianity’s development from humble origins to a great religion.

It is the result of later generations stripping the original decoration from the exterior.