Utilize the input text as a context reference, choose the right relationship between GMC and truck 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.

GM Posts the Industry's Largest Retail Sales Increase on Double-digit Gains in Pickup and Crossover Sales Tue, Sep 1 2015 Chevrolet crossovers up for ninth consecutive month - best August ever Chevrolet truck sales up for 16th consecutive month Double-digit sales increase for GMC pickups Buick crossovers up 28 percent Cadillac SRX up 52 percent Commercial deliveries up for 22 consecutive months

Answer: product_or_material_produced