The best answer is A. Violent riots were started in several Chinatowns by nativists who were angry and resentful of newcomers. Nativists believes in focusing in the protection of the interests of the native people or the original inhabitants in an area. They are always against newcomers or immigrants.
During formal discussion, mental notes could help you maintain your focus/attention for the point that given by another speaker so you could give your opinion or counter argument later.
This will give the impression that you're an attentive and a competent person.
The Answer is in fact D. After the attack on Pearl Harbor the U.S. declared war on the Axis Powers, not just Japan.