A senior executive asked an administrator to change the default background of the executive's machine, which uses XDM. Which of the following files would the administrator edit to achieve this?

The `/etc/X11/xdm/Xsetup` script is run by XDM after the X server starts but before the login window is displayed. This script is commonly used to set the root window background, load fonts, or perform other initial display setups for the X session managed by XDM.

`/etc/X11/xdm.conf` is not a standard configuration file for XDM; the main configuration is typically in `xdm-config`.

`/etc/X11/xdm/Defaults` (or `xdm-config`) contains global XDM configuration settings like display manager options, but not specifically the script for setting the graphical background *before* login.

`/etc/X11/defaults.conf` is not a standard XDM configuration file.