I think its shortage of good farmland. The US had a lot of good usable farmland
C. Is a Factual Statement
This one is tricky, because scientific law can explain an observation, or be used to make a prediction, but I believe that C. is the most correct of the 4 answers.
It began in the 1880s but started in the United States and England around 1920s
Under the Constitution, the president is the federal official that is primarily responsible for the relations of the United States with foreign nations. The president appoints ambassadors, ministers, and consuls (subject to confirmation by the Senate) and receives foreign ambassadors and other public officials
