What is the relationship between 'Mack Trucks' and 'Truck' in the context of the input sentence.
Options: business division, founded by, product/material produced, distribution format

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