The correct answer is - B. Former colonial nations became independent.
After the World War II, the nations that were under the rule of the colonial powers, one by one started to gain independence. That was a result of multiple reasons. One reason was the economically and military exhausted nations that were the colonial powers, thus they had to focus on their own rebuilding and development, and were not able to invest and control in the colonies. The international pressure was constantly increasing, as well as the formation of numerous independence movements. There was lot of revolt and desire for independence among the people in these nations. Considering everything, the colonial powers simply granted these nations independence without any military conflicts being involved.
