Answer: Abraham Lincoln set the African-American slaves free with Emancipation Proclamation.
The authoritarian governments of the world in 20th century have usually existed in Africa and West Europe, along with South America
Explanation:
There was a visible rise in authoritarian sentiment across world din the time of the twentieth century leading to many nations hoping that form of the government or being simply taken over by the dictators and it happened all over the world
Most of the nations that are now democracy had been monarchies for some time before they turned back and it has been the same story across the world and specially in newer countries like in Africa and South America
It has also happened in the old, decolonized world in the middle east and with the rise of fascism in Europe.
D is the closest answer. The problem was that the naval oil reserves were located in Teapot Dome Wyoming and these reserves were secretly transferred to the Mammoth Oil company. There was no bid. There was no fairness in the transaction. It was motivated mostly by greed, it seems. Harding's administration was riddled with problems. This was just one of them.
US has most of its money invested in China and China will not let the US pay off its debt with them.