> ac /# mount_msdos /dev/wd0c /mnt
> mount_msdos: mount: Device not configured
> ac /# mount_msdos /dev/wd0d /mnt
> mount_msdos: mount: Invalid argument

Try

mount_msdos /dev/wd0e /mnt

To learn that this was the right thing to do (if it is), you could
have looked at the in-core disklabel by typing

disklabel wd0

	-- Robert Kennedy