Based on documentation,
The only 2 African countries that were able to keep their freedom from European imperialism were;
B: Ethiopia and Liberia.
Ethiopia is currently the worlds oldest independent country and Liberia was founded to support the U.S. in relation to slavery in 1821.
I hope this has aided you and is sufficient.
Cheers! <span />
B. and D.
I believe, but I am not 100% sure!
The Mexican American War heightened tensions over slavery in that there were many disagreements over whether the new territories won from Mexico should be free or slave territories. The Wilmot Proviso, created to solve the problem, ended up slitting parties on regional areas.
Good luck :)
The 17th parallel was the provisional military demarcation line between North and South Vietnam established by the Geneva Accords of 1954.