The correct answer is D) join the "Peace Corps."
The MOST impactful way American citizens can impact world affairs is to join the "Peace Corps."
The "Peace Corps" aims to promote peace in the world and better relations between countries through tolerance and cooperation. Americans really could be of a lot of help if they join this organization. World affairs are a big issue these days, and people's participation in different projects abroad can represent a big difference in promoting change an peace.