DETROIT - General Motor's (NYSE: GM) Chevrolet, Buick, GMC and Cadillac brands sold 272,512 vehicles in the United States in July 2015, a 6 percent increase and the four brands' best combined July since 2007.
Utilize the input text as a context reference, choose the right relationship between 'GMC' and 'DETROIT' from the options.
Options: distributed by, stock exchange, creator, headquarters location