How do I remove unwanted field from content submission form

I installed the classified ad module . Curiously however , in the submit form for classified ads, there is a "required" field named "Classified ads" with empty drop down select values. I did not put this field there and can't figure out how it got there. Bottom line is that , because a value is expressly required in the drop down select (which is empty of values) nobody is able to submit anything because an error will be shown that the field is required. I want to remove this field or in the alternative put in some dummy values to select. Can someone help ?