Final answer:
World War I affected the U.S. economy by creating debt from loans owed to European nations and decreasing factory production due to labor shortages.
Step-by-step explanation:
World War I affected the U.S. economy by creating debt from loans owed to European nations (option A) and decreasing factory production due to labor shortages (option B). The U.S. government lent large sums of money to the European nations to support their war efforts, which created a significant amount of debt. Additionally, many American workers were recruited to join the war, leading to labor shortages and decreased factory production. These two factors had a significant impact on the U.S. economy during World War I.