Question

On February 24, when Hall sensed that the Zimmermann telegram would tip the balance in favor of the U.S. joining the Allied forces, the British home secretary presented the telegram to President Wilson. One week later, news of the Zimmermann telegram was splashed across the front page of American newspapers. On April 6, 1917, the Congress of the United States declared war on Germany and its allies.
Although the battlefield mayhem continued for another year, the added strength of U.S. troops proved to be too much for Germany. David Kahn, a leading authority of cryptography, wrote this about the Zimmermann telegram: "Never before or since has so much turned upon the solution of a secret message."
–The Dark Game,
Paul Janeczko
Which best describes the author’s viewpoint in this passage from an earlier chapter of The Dark Game?
1.The author is suggesting that the telegram sparked the US decision to go to war.
2.The author believes the telegram added to the strength of US troops.
3.The author claims that the telegram had no effect on the course of events.

Answer 1

I would say "1. The author is suggesting that the telegram sparked the US decision to go to war." 
I would say this because "...Hall sensed that the Zimmermann telegram would tip the balance in favor of the U.S. joining the Allied forces...presented the telegram to President Wilson." This implies that because the telegram was sent, the U.S. joined the Allied forces.  

Answer 2

(A) The author is suggesting that the telegram sparked the US decision to go to war.