Cosmic Rays in the Milky Way Are Important Because

Cosmic rays in the Milky Way are important because:

A) these energetic photons easily penetrate the Earth's atmosphere
B) they can be collected and used to generate electricity
C) they have about the same energy as that contained in magnetic fields and in the kinetic energy of gas clouds
D) they carry information about AGN in external galaxies
E) they can influence the motion of stars in the halo