The Treaty of Versailles caused problems in the future because it treated Germany in a very harsh manner. The people of Germany were angered by the harsh and, in their minds, unfair treatment. In addition, the treaty weakened the German economy, leading to economic problems that also angered Germans.
One theory is that the native Americans where the first to come to America but this is just an old wives tale.
South Korea is a democratic country - option d. (the potentially hostile neighbor is North Korea, which is both totalitarian and communist/socialist; but South Korea is not any of those).
