"B is the answer because the Europeans were immune to the virus and the Indians weren't so they grew very ill which helped the Europeans."
the united states solution i believe was the best because they were able to keep themselves up enough to last to world war 2 when they started to increase jobs because they had to build war machines like ships and tanks ect and since they had to do it fast they had to hire more people instead of some of the other countries how lessened the value of their money such as great Britain
the following is true about the souths war effort
hope this helped!
1978 is the answer comrade