Answer:
The correct answer and the main change that took place in the United Nations between 1945 and 1965 is B. It more than doubled in size.
Step-by-step explanation:
The United Nations began to operate in 1945 and it formed by 50 governments. By 1965, the United Nations doubled in size due to the process of widespread decolonization that started in the 1960s. Because of this process, about 80 former colonies became independent territories that were monitored by the Trusteeship Council