The correct answer is option C. The development of social classes. In the earliest civilizations, historians believed that trade was connected to the development of social complexity. This theory is supported by the fact that trade coincided most with the development of social classes.
The more developed a community was,in terms of organizing its citizens and having different social sectors in it, the more advanced its trade was. The appearance of social classes within a community was a sign that this last one was growing and developing, and that was seen in its trade and commerce.