The content and context of a 1917 American poster typically reflect the sentiment of the time, particularly the push for U.S. involvement in World War I. Based on this historical context, the most appropriate response would be:
A. should fight Germany to protect the borders of the U.S.
During this period, many propaganda posters encouraged recruitment and highlighted the need for the U.S. to join the war effort against Germany, promoting the idea that involvement was necessary for national security and the defense of democratic values.