What is evidence for the existence of dark matter?
A. There is not enough mass in galaxies to produce the gravitational force that exists, so dark matter must make up the difference
B. The galaxies are too bright for the total amount of energy they produce, meaning dark matter must exist to amplify the reflections of the light
C. The momentum of galaxies is too high to match their current moving velocities, meaning that there must be dark matter to increase the momentum of those galaxies