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
What is the relationship between 'GMC' and 'truck' in the context of the input sentence.
Options: developer, chief executive officer, product/material produced, manufacturer