The correct answer is C. Trusteeship Council.
The Trusteeship Council was established in 1945 to oversee the administration of Trust Territories, which were territories that were not self-governing and were placed under the administration of a trusteeship agreement with the United Nations. The Trusteeship Council was responsible for promoting the political, economic, social, and educational advancement of the peoples of the Trust Territories, and for ensuring that they were prepared for self-government or independence.
The Trusteeship Council completed its work in 1994, when the last Trust Territory, Palau, became independent. The Trusteeship Council has since been in a state of suspension, but it has not been formally dissolved.
The Economic and Social Council (ECOSOC) is one of the six principal organs of the United Nations. It is responsible for promoting international economic and social cooperation and development, and for coordinating the economic and social work of the United Nations and its specialized agencies.
The International Court of Justice (ICJ) is the principal judicial organ of the United Nations. It settles legal disputes between states and gives advisory opinions on legal questions referred to it by authorized UN organs and specialized agencies.
The Secretariat is the administrative organ of the United Nations. It is headed by the Secretary-General, who is appointed by the General Assembly on the recommendation of the Security Council. The Secretariat is responsible for carrying out the day-to-day work of the United Nations.