a. It revealed Germany’s plan to form an alliance with Mexico.
The telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, von Eckhardt, offered United States territory to Mexico in return for joining the German cause and thus led the U.S to enter the war
Option A is the right answer that it revealed Germany’s plan to form an alliance with Mexico.
When the first World War broke out, president Wilson declared America's intent to stay neutral in the war. A series of events including the German Submarine Warfare which resulted in the sinking of the American Ships claiming many American's lives, the Zimmerman telegram in which German promised Mexico to form an alliance against America led Wilson to deliver the War Message to the Congress. The United States then entered the war by claiming their participation for saving the democracies of the World
