sentences:  A major factor leading to the cancellation was lack of product support by Chevrolet dealers.In contrast to Chevrolet (and other General Motors brands), GMC required all franchisees to sell and service the GMC product line in its entirety.In addition to light trucks, this meant a potential GMC franchise needed the ability to support medium-duty trucks, heavy-duty commercial trucks, P-chassis, the GMC Motorhome, and all bus chassis.