The Idea of Dark Matter Arose to Explain Gravitational Effects

The idea of dark matter arose to explain gravitational effects observed in galaxies and clusters of galaxies. However, studies of the early universe (especially of the cosmic microwave background and of chemical abundances) also tell us something about dark matter. What do they tell us?

A) They do not support the conclusion that dark matter is the dominant form of matter in the universe.
B) They tell us that dark matter was produced during the era of nuclei.
C) They add further support to the idea that dark matter really exists and is made of non- ordinary (nonbaryonic) matter, such as WIMPs.
D) They tell us that dark matter probably exists, but that it must be made of ordinary matter in the form of dim objects in galactic halos.