Which term does not belong to the set. A. Sussex pledge B. Lusitania
C. attack
D. Zimmerman Note

Zimmerman notes

Explanation:

Explanation:

On the afternoon of May 7, 1915, the British ocean liner Lusitania is torpedoed without warning by a German submarine off the south coast of Ireland. Within 20 minutes, the vessel sank into the Celtic Sea. Of 1,959 passengers and crew, 1,198 people were drowned, including 128 Americans. The attack aroused considerable indignation in the United States, but Germany defended the action, noting that it had issued warnings of its intent to attack all ships, neutral or otherwise, that entered the war zone around Britain.