What Perception of the Milky Way Galaxy Did Astronomers Have

Multiple Choice

What perception of the Milky Way Galaxy did astronomers have in 1900?

A) They believed that the Earth rested inside concentric spheres, with the Milky Way stars fixed to the outermost sphere.
B) They believed that the Milky Way was one of billions of galaxies in the universe.
C) They believed that the Milky Way was the entire universe.
D) They believed that, because the Sun was at the center of the Milky Way, it was impossible to see the rest of the universe.
E) They believed we were one of billions galaxies in an expanding universe.