Utilize the input text as a context reference, choose the right relationship between 'Volvo' and 'Truck' from the options.
Options: brand, founded by, product/material produced, owner of

In what was then the largest environmental enforcement case in U.S. history, companies including industry leaders Caterpillar Inc., Cummins Engine Co., Mack Trucks and Volvo Truck Corp. agreed to pay $83.4 million in fines and reprogram the computers.
product/material produced