What file should you edit to change the default greeting for it?

You have just set up the Gnome Display Manager as your default display manager. What file should you edit to change the default greeting for it?

A.
/etc/X11/prefdm

B.
/etc/X11/XF86Config

C.
/etc/X11/gdm.conf

D.
/etc/X11/gdm/lnit/Default

Explanation/Reference:
see http://library.gnome.org/admin/gdm/stable/configuration.html.en and http://library.gnome.org/admin/gdm/stable/configuration.html.en#greetersection