What effect did John Hay's open door policy letters have on the imperial powers of Britain, France, Germany, Russia, and
Japan?
(1 point)
O It provoked the imperial powers to declare war on the United States.
• It caused the imperial powers to restrict trade in their trade with China.
• It warned the imperial powers that the United States would soon declare war on China.
• It signaled to those powers that the United States would take a larger role in world affairs than before.