It separates North and South Korea. It was the border between them since the Korean war that was led over the unification of the country. The northeners wanted to have a fully communist Korea while the southerners wanted to have a western oriented Korea.
B. It was a challenge to decide how to divide forces and protect two coasts.
C. New immigrants worked mostly in unskilled jobs.
Hope this helps
The correct answer is B. Negotiating a treaty with Mexico.
Explanation
Foreign policy is the name by which the decisions and actions taken by a State are known to favor the national and international interests of the countries involved. In short, foreign policy groups the agreements, negotiations, and decisions of two or more nations to establish economic, political, and social relations. So if a country like the United States establishes negotiations for a treaty with Mexico, it would be a matter of foreign policy because it involves the interests of two countries and their needs and interests. According to the above, the correct answer is B. Negotiating a treaty with Mexico.
