Answer:
Carving of new states in Africa by European power caused land disputes, most notably the Hutus and Tutsis, who are still in conflict to this day
Explanation:
I'm not sure if this is exactly what you're looking for, but I hope I helped :)
The answer would be B I believe
Christopher Columbus is the answer most likely to be correct but, there is an argument for Leaf Erikson
I believe it is the 'domino theory' as one country falls then pushes the next to fall and so on and so forth. Just like dominos.
