B. unrestricted submarine warfare and the zimmerman telegraph
The Zimmermann Note, or telegram, was sent by German Foreign Minister Arthur Zimmermann. He sent it to his ambassador in Mexico and the goal was to get Mexico to become an ally of Germany. It said that Germany would, after it won the war, give the Southwestern US back to Mexico. The United States entered the war because of the Germans' decision to resume the policy of unrestricted submarine warfare, and the so-called "Zimmerman telegram."
The answer I think to this is C. Eisenhower
Hope this helps in anyway? and sorry if it's wrong.
The Commerce<span> Clause describes an enumerated power listed in the United States Constitution (Article I, Section 8, Clause 3). The clause states that the United States Congress shall have power "To </span>regulate Commerce with foreign Nations<span>, and among the several States, and with the Indian Tribes." hope this helps </span>