The correct answer is B. After the German attack on the USS Greer, Roosevelt changed the neutrality act so ships carrying war materials could be armed.
The USS Greer was the first ship of the US Navy that was attacked in the Atlantic by a German submarine, over three months before the declaration of war by the German Reich to the United States. In response to this incident, President Franklin D. Roosevelt instructed US Navy ships not to wait for an attack, but to strike immediately if they sighted an Axis vessel.
