Refer to the input text as context and select the correct relationship between 'GMC' and 'Detroit' from the available options.
Options: operator, publisher, headquarters location, manufacturer

Furthermore, as Detroit automakers continue to rely on full-size trucks and SUVs for a majority of their profits, it's a good sign for investors that GM's Chevy and GMC brands sold more than 86,000 pickups in July -- GM's best figure since July 2006.
headquarters location