The correct answer is D.
After World War II, the United States was afraid that the idea of communism would spread to countries who were unstable, financially speaking, after World War II. If communism spread, this would allow the Soviet Union to continue to gain power and influence. This would not be good for the US, as they believed a communist system would lead to more government corruption and less freedom for citizens.
To ensure this doesn't happen, George C. Marshall introduced the Marshall Plan. This plan would end up giving $13 billion to European countries in order to support their economy. From there, the countries could create a political and economic structure similar to the one that the United States uses.