The Extreme Redshifts of Quasar Spectra Are Caused by

The extreme redshifts of quasar spectra are caused by

A) very high recession speeds of the sources away from our Galaxy.
B) the high gravitational fields at the surfaces of these quasars (gravitational redshift) .
C) absorption of all but the red parts of the quasar spectrum by intergalactic matter.
D) Zeeman effects from the very intense magnetic fields in the vicinity of the source.