Question

which of the following upset the united states and moved it closer to entering the war?
○ the zimmerman telegram
○ restrictions on u - boat warfare
○ the british blockade
○ ammunition in the cargo of the lusitania

Explanation:

The Zimmermann Telegram was a secret diplomatic communication from Germany that proposed a military alliance with Mexico against the US. This revelation outraged the US public and government, pushing the US closer to entering World War I. Restrictions on U - boat warfare were a German attempt to appease the US (initially), the British blockade was against Germany and not a direct trigger for US entry, and the fact that the Lusitania had ammunition was used by Germany to justify its sinking, but the Zimmermann Telegram was a more direct and impactful event leading to US entry.

Answer:

the Zimmermann Telegram