A:the U.S. declared war on Germany.
B:the U.S. declared war on all three Axis powers.
C:Germany declared war on Japan.
D:the U.S. decided to expand its military.
I would believe it's answer D because the US did not go to war with the Axis in WWII until after the attack on Pearl Harbor. Answer C is also incorrect because Japan and Germany are allies during WWII.
