Options 1, 2, and 3 in the Auto Attendant cannot be altered or disabled. You can change the various prompts that are played at various times in the Auto Attendant, but the basic operation of the Auto Attendant will not be changed.
When someone presses 1 to continue the call, the number stored at:
Voice Services -> Auto Attendant -> NumberOnNoInput
is dialed. This defaults to 0 which rings the PHONE Port.