Answer:
B) Declare war on Germany
Step-by-step explanation:
The Zimmermann telegram was a telegram sent by Arthur Zimmermann, Minister of Foreign Affairs of the German Empire, on January 16, 1917 (during the First World War), to his ambassador to Mexico, Count Heinrich von Eckardt. In it the ambassador was instructed to bring to the Mexican government a proposal to form an alliance against the United States. It was intercepted by the British espionage services, and its content accelerated the entry of the United States into the war.