How did the United States become involved in World War I?

The involvement of the United States in World War I was primarily driven by a series of events that escalated tensions and ultimately led to its entry into the conflict on the side of the Allies in 1917. One of the key factors was the German practice of unrestricted submarine warfare, which significantly affected American shipping and trade. This strategy by Germany resulted in numerous American lives lost, particularly with incidents like the sinking of the Lusitania, which fueled public outrage and anti-German sentiment within the United States.

Additionally, the interception of the Zimmerman Note, in which Germany proposed a military alliance with Mexico against the U.S., heightened fears of direct threats to U.S. sovereignty and security. This diplomatic blunder further galvanized American opinion in favor of entering the war against the Central Powers. The combination of these provocations, along with the growing economic and political ties with the Allied nations, created a situation where the U.S. could no longer maintain its stance of neutrality. Therefore, the correct option accurately summarizes the reasons for U.S. involvement in World War I, highlighting how specific events prompted the nation to join the conflict in support of the Allies.