Generalizing from sherif's study of conflict resolution between two groups of child campers, you might suggest that the best way for the united states and china to improve their relationship would be to

In this very same paradigm, we can suggest that in order for these two world nations to come to a better relations provide them a single enemy to battle. This is to focus on more important and urging matters such as climate change, poverty alleviation and others than competing each other's interests.

Im pretty sure the answer is d.) is more densely populated.