Thanks for the question! So remember, this is a main point question. Answer choice (A) says that this main point is that although the contrary to a traditional assumption of theoretical economics, the behavior of participants in the Ultimatum Game shows that they DON’T make economic decisions out of rational self-interest. But is that what the passage is about? No, it’s the opposite! The passage is about how the Ultimatum Game can actually be explained by rational self-interest! For example, there are reputation incentives and things like that that people should be interested in.
Hope this helps! Feel free to ask any other questions that you might have.
