Halo Stars near the Sun Are Distinguished from Disk Stars

Halo stars near the Sun are distinguished from disk stars by what characteristics?

A) low heavy-element abundances and low relative velocities
B) high heavy-element abundances and high relative velocities
C) low heavy-element abundances and high relative velocities
D) high heavy-element abundances and low relative velocities
E) equal heavy-element abundances and high relative velocities