What did Germany do in 1915 that tested the United States’ neutral stance in World War I?

In 1915, a German submarine sank the British passenger liner Lusitania. The ship was carrying passengers, including Americans, and its sinking caused outrage in the United States, putting pressure on the country’s neutral stance. Therefore, the correct choice is “It sank the Lusitania, which was carrying passengers to Europe.”

AI-written and checked against the verified answer.