The Answer to your question is "B"
Federalism and the 10th amendment work together--the 10th Amendment states that if something is not covered by the Constitution and there is no specific federal power, then the power goes to the state.
Federalism is the principle that government should be divided between a central power and regional powers. In the case of the 10th Amendment, if the central power doesn't have explicit power to do something then the states have the power to do so.
Answer:
The impact of WWII on the history of the world is that Millions of Germans and Japanese were forced out of the territories they lived in and sent back "home. Also the victors dismantled their former enemies' ability to make war by dismantling factories.
