The right answer for the question that is being asked and shown above is that: "a buyer in a marketplace." Each of the following is an example of labor except a buyer in a marketplace. A buyer is not part of a labor.
I think to answer this group we need the "following groups", I mean that's just a thought. Correct me if i'm wrong.
Answer:
B. The desire of European nations to remain isolated, not forging relationships with neighbors.
Columbus wanted portugal to sponsor him but he ended up having Spain give him money.