Answer:
The correct option is C: "as evidence that Balin is not acting purely in his self-interest."
Explanation:
The fact that Balin actually had the choice to purchase the same quality of cocoa at better or lower prices, but however decides to purchase the fair trade cocoa which was more expensive just to show his concern for the right of workers and environmental sustainability, Behavioral economist would see this as evidence that Balin is acting not because of his self-interest but passion for the rights of others.