Utilize the input text as a context reference, choose the right relationship between GMC and DETROIT from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

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.

Answer: headquarters_location