Concept:The main difference between a trust and a cartel is the degree of independence each member firm keeps after coming together.Explanation:In a cartel, independent firms in the same trade come together to regulate output or prices.Each firm in a cartel remains independent and continues to manage its own affairs.In a trust, firms combine and transfer their shares or management powers to a central board of trustees.The individual firms in a trust therefore surrender most of their independence to the trustees.This difference in the level of independence allowed to the individual business units is what separates a trust from a cartel.Answer:D. Trust and Cartel