In a Collision Between Clusters of Galaxies, What Happens to the Hot

Multiple Choice

In a collision between clusters of galaxies, what happens to the hot gas and dark matter,based on observations of the "bullet cluster"?

A) The gas stays with the luminous matter, but the dark matter moves on.
B) The dark matter stays with the luminous matter, but the gas moves on.
C) Both the dark matter and gas continue their motion, leaving behind the luminous portions ofthe galaxies.
D) The luminous matter moves on, leaving behind the dark matter and gas.
E) The dark matter moves with the luminous matter, leaving behind the gas.