One Way Astronomers Deduce That the Milky Way Has a Disk

One way astronomers deduce that the Milky Way has a disk is that they

A) see stars arranged in a circular region around the north celestial pole.
B) see far more stars along the band of the Milky Way than in other directions.
C) see a large dark circle silhouetted against the Milky Way in the Southern Hemisphere.
D) see the same number of stars in all directions in the sky.
E) None of these choices is correct.