I do believe that, after research, it is C, Coltan.
Correct me if I am wrong, but do have a good day!
War Communism in Russia involved all of the following except forcing peasants to to join the military. The correct option among all the options given in the question is option "c". It was a fact that peasants had to supply food after keeping a bare minimum for themselves. The banks, factories, mines and railroads were all taken over by the government.
The league of Nations, I believe.
*Columbian
The Columbian Exchange greatly affected almost every society on earth, bringing destructive diseases that depopulated many cultures, and also circulating a wide variety of new crops and livestock that, in the long term, increased rather than diminished the world human population.
Hope this helped
