Measurements of stellar velocities show that a galaxy gets its basic shape from the way that the stars move within it. The difference between the motion of stars in the central roundish bulge of a spiral galaxy and the surrounding flattened disk with spiral arms. Given that elliptical galaxies are relatively round, ranging in shape from spheres to more squished spheroids similar to an American football, which of the following statements most accurately describes the orbits of stars in an elliptical galaxy?
A. All the stars orbit in the same direction around the center of the galaxy.
B. The stars take spiral orbits from the bottom to the top of the galaxy, and then back down again.
C. The stars all have irregular orbits in all directions about the center.
D. The stars in half the galaxy all orbit in one direction around the center, and the stars in the other half orbit together in the opposite direction.