Question

Urgent!!! Which of the following was most crucial in bringing about US abandonment of neutrality during WWI?

a. British propaganda
b. German use of submarines against merchant and passenger ships.
C. Germany's violation of Belgian neutrality.
d.
Fear of an Allied defeats and the loss of billions in unpaid loans.

Answer 1

It was because of Germany's use of submarines against neutral passenger and merchant ships. The unrestricted submarine warfare was agitating for the US, the last thing that provoked the Americans was the Zimmerman telegram.

Hope this helps.