Correct answer: B. General Assembly
Explanation: Direct answer: Option B, the General Assembly. The Universal Declaration of Human Rights was adopted by the United Nations General Assembly on 10 December 1948. The reasoning is: distinguish an organ that represents all member states from organs with narrower functions, then recall that the declaration was approved by the Assembly as a major statement of common human rights. Option B is correct. Option A, the Security Council, mainly deals with international peace and security and uses a different decision process. Option C, the Secretariat, carries out administrative and coordinating work under the Secretary-General; it did not adopt the declaration. Option D, the Trusteeship Council, was created for trust territories and is not the adopting body here. The declaration itself is not a treaty, but it was an important UN General Assembly document. Memory cue: UDHR, 1948, General Assembly.