GREENFIELD — Massachusetts State Police have arrested three men from Vermont who were caught allegedly trafficking the powerful opioid fentanyl and other drugs in Greenfield.A trooper on routine patrol on Interstate 91 late Tuesday night spotted a northbound car with an unreadable license plate. The trooper stopped the vehicle after it took an exit into Greenfield.Police say a search of the vehicle yielded 70 bags of fentanyl, 22 grams of cocaine, scales, drug paraphernalia and five 12-gauge shotgun shells.