GRE Text Completion: JiJing 1373-GRE填空机经1373题 - G270US2ES3Z62Q84A

Advertising, formerly called the last resort to create or distribute music, has transformed itself to ____________ of music that would otherwise be unheard. A. a camouflage B. a derivative C. a champion D. an impediment E. a promoter F. an impetus