A Few Decades Ago,there Was Great Controversy Among Astronomers Over

A few decades ago,there was great controversy among astronomers over the question of quasar distances,with some arguing that quasars are much nearer than application of Hubble's law would seem to imply.Why do nearly all astronomers now agree that quasars really are quite far away?

A) We now have images and spectra that show quasars to be embedded at the centers of distant galaxies and within distant galaxy clusters.
B) All quasars have large redshifts.
C) Now that we can explain bright quasar emission with power due to the presence of supermassive black holes,there is no reason to doubt that quasars are far away.
D) No one could think of a way to explain quasar speeds if they are nearby,so we concluded they must be far away.