Astronomers Now Know That Surrounding the Main Body of Our

Astronomers now know that surrounding the main body of our Galaxy (which our various kinds of telescopes have shown to us) and our fainter halo of stars there is

A) only the empty space that lies between galaxies
B) a series of hundreds and hundreds of nearby small galaxies, held in place by the Milky Way's gravity
C) an invisible halo made of what astronomers are calling "dark matter"
D) a set of huge clouds with many interesting molecules (like alcohol, carbon monoxide, and ammonia) in them
E) a pair of long, bright jets of materials produced by a massive black hole and its accretion disk