Bill Clinton was not the first
This was an edit
"Raw materials were shipped from Africa to European industries"
I believe you answer is C. But don’t quote me on that.
Serfs may eventually work their way to freedom (usually not), if you know the term tenant farmers, individuals who work on a property with some believe that eventually they may pay their debts off and become a freeman. An enslaved person, will never believe that they will eventually become free.
-My opinion anyway (probably wrong) but worth a try.
The reasons why World War I happened are multiple and complex. One important is the fact that Germany lacked any real colonies prior to World War I, at least compared to the other nations which had massive and important colonies such as Great Britain or France. Another thing was general dissatisfaction and nationalism within the Austro-Hungarian empire.