The Wagner act provides American workers with the legal right to conduct a strike.
This gives the power to the American workers to form a union and opened up discussions with job owners regarding fair working condition.
The Social Security act provides various forms of welfares for American Citizens, especially for the old citizens and the disabled.
By appointing the chair and a majority of the members
Nativism is hostility toward immigrants by native-born people (nativists). Nativists extremely dislike immigrants, and, therefore, opposed immigration.
I think your answer should be A. Nullification. (basically Null = void = Not accepted). Hope this helps! ^-^