Our Galaxy Is Suspected to Be Surrounded by a Galactic

Multiple Choice

Our galaxy is suspected to be surrounded by a galactic corona because the disk of the galaxy

A) rotates faster than expected in its outer region.
B) rotates more slowly than expected in its outer region.
C) rotates faster than expected in its inner region.
D) rotates more slowly than expected in its inner region.
E) is much flatter than expected.