Dark Matter Is Matter That Gives Out No Observable Radiation

Multiple Choice

Dark matter is matter that gives out no observable radiation and is detected by its gravitational interaction alone. Which of these does NOT provide direct evidence for dark matter?

A) separation of visible and dark matter in collisions of galaxy clusters
B) emission from hot intergalactic gas in galaxy clusters
C) gravitational lensing by unseen objects
D) insufficient visible mass to bind galaxy clusters gravitationally