Very similar to Jesus' flip flop
Answer: The answer is -- (A) The Cold War.
Explanation: The Cold War was a period of geopolitical tension between the Soviet Union and the United States and their respective allies, the Eastern Bloc and the Western Bloc, after World War II. The period is generally considered to span the 1947 Truman Doctrine to the 1991 dissolution of the Soviet Union. Hope this helps!
At first it was mostly poor americans from the east, hoping to make a lot of money. By the time they began digging into mountains, less and less americans agreed to do the dangerous work. using explosives and pickaxes to get at a chance for money wasn't worth it to them, so many companies began hiring chinese immigrants because they would work for much less, and were willing to risk it for a place to live and food to eat.
Most of Europe's population was killed during the time periods 1347 - 1350 with 30% to 65% of its population dead. The religions had like a downfall. Which all had a great impact on European history. I hope this helps! <3