Which of these was a factor in the United States entrance in World War I?

Question

Responses
A the invasion of Polandthe invasion of Poland
B Japan's invasion of ChinaJapan's invasion of China
C The Axis threat to the Panama CanalThe Axis threat to the Panama Canal
D German unrestricted submarine warfare

Answer 1

D. German unrestricted submarine warfare

German unrestricted submarine warfare was a significant factor that contributed to the United States' entrance into World War I. The policy led to the sinking of ships, including those carrying American passengers, which raised public outrage and ultimately influenced the U.S. government to join the war.