I believe the answer is Gold.
Gold was a very hot commodity at that time because before we use paper/digital money like today, Gold was made as material to make a type of money with more intrinsic value.
The abundance of this natural resources led to many European empire came and started their colonization in AFrica.
The correct answer is:
a. Cotton Mills
During the Reconstruction Era, Cotton became a protagonist in the industrial growth of the Southern States. Southern capitalists sank Money into cotton rather than factories or land. More precisely, they invested in slaves; the average slave owner held almost two-thirds of his wealth in slaves in 1860, much less than he held in land.
Fascism was a new ideology that emerged during the Great Depression as a solution to economic hardship, a system that would unify every aspect of life under one rule and one direction. The direction of an dictator. The treaty of Versailles was the result of WWI that would punish Germany and other nations in the Central Powers. Mainly Germany, the treaty was seen as unjust and unfair, they lost land, large parts of the military, lost money, more than anything else though, they got their national pride ripped from them. The Great Depression was a period of economic downturn where nations across the world lost money and faced crisis causing many nations to turn to new ideologies and people to lead them.
The answer that best fits the blank provided above the first option. President Ronald Reagan is the 40th President of the United States and according to his political view, this can be summarized by giving less favor to the government at home and be an anti-communist abroad.