The correct answer is C. It caused public opinion to turn against the Germans even more.
The RMS Lusitania was a British transatlantic that sink in the British sea due to an attack by the German Navy during the WWI. In that ship there were British and American citizens that died after the attack. In total there were 1198 dead people. The United States remained neutral towards the war until this event, which turned the American public opinion against Germany. It was one of the main reasons for the entry of the United States in the war against Germany.
