There is an option for what sort of numbering to use, including an option for no numbering. Edit the question and choose that. (The answernumberingABCD string in the language pack is the name of the option that is displayed in the editing form. Those values are not intended to be used when printing the question.)
Also, there is a setting for admins to control what type of numbering is used by default when a new multiple choice question is created.