Answer:
Early merchants sold their goods at (a.) fairs.
Step-by-step explanation:
It wouldn't make sense to sell their goods at their homes because they don't pass by a lot of people in their own home. It also wouldn't make sense to sell their goods at the docks or on ships because people are most likely busy at those places. So at the fairs, people go there to have fair and relax, and sometimes buy things.