What Do Halo Stars Do Differently from Disk Stars

What do halo stars do differently from disk stars?

A) They orbit the galactic center with many different inclinations, while disk stars all orbit in nearly the same plane.
B) They remain stationary, quite unlike disk stars that orbit the galactic center.
C) Halo stars explode as supernovae much more frequently than disk stars.
D) They orbit the center of the galaxy at much lower speeds than disk star.