The correct answer is: "increasing the monetary supply".
During WWI all the countries, included the US, abandonned the Gold Standard. The different curriencies were not tied to the gold reserves anymore and countries financed the massive war expenditures by printing money. They increased the amount of money in circulation in the economy, which led to generalized inflationary tendencies all over the world.
On May 8th 1945, the Allies accepted Germany's surrender, about a week after Adolf Hitler had commited Sui**** VE Day celebrates the end of the Second World War on May 8th 1945.
