听力原文：The United Nations celebrated the 60th anniversary of its Charter on Monday with

听力原文： The United Nations celebrated the 60th anniversary of its Charter on Monday with speakers addressing the UN General Assembly. UN secretary general Kofi Annan said the UN had both successes and failures in carrying out the pledges of the Charter. The UN Charter is a constituent of the organization. It was signed in San Francisco on June 26, 1945 by the 50 original member countries. It took effect on October 24, 1945 after being approved by the five founding members, China, France, the Soviet Union, United Kingdom and the United States. And the majority of the other counties that signed the Charter. The Charter is constitutional trading, all countries signed it are bounded by its articles. It states the Charter comes first, above all other treaties. Its main purposes include the prevention of new conflicts, building peace and protecting human rights and social progress. The most important chapters are those dealing with enforcement powers of UN bodies. Their describe, for example the security councils power to investigate and mediate disputes. They also describe its power to authorize economic, diplomatic and military sections as well as the use of military force to resolve the disputes. The UN late last year review the proposal to overhaul the reorganization including the security council. This could be the most comprehensive UN reform. since its foundation.

The UN Charter went into effect after ______.

A．it was signed by the 50 original member countries

B．it was approved by the founders and other member countries

C．it was approved by the founding members

D．it was signed by the founding members

请帮忙给出正确答案和分析，谢谢！