Use at your own risk.
Check for /var/lib/spamassassin/3.004006/updates_spamassassin_org/10_default_prefs.cf but do not edit that file!
If you don't use the newest version, then change 006 to 005 or earlier.
That template contains what you selected. Copy this part to the bottom of your /etc/mail/spamassassin/local.cf file and adjust the text there to your needs.
When finished, save the file and restart spamassassin.