What Is the Significance of the Interception of the Zimmermann

What is the significance of the interception of the Zimmermann telegram?

A) It showed that Germany had no interest in collaborating with Mexico and thereby strengthened the trust between the United States and Mexico.
B) It announced Germany's decision to wage unrestricted submarine warfare and caused angered Americans to call for war.
C) It announced the addition of three countries to the Central Powers, leading the United States to stall entering the war.
D) It caused the United States to break diplomatic relations with Germany and begin sending supplies to the Allies.
E) It tipped off J. Edgar Hoover that Germans had infiltrated the FBI and caused the government to clamp down on background checks.