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.

The increase was particularly strong for the GMC truck line, where sales soared 23.8 percent to 47,386.

Answer: product_or_material_produced