The correct answer is the following: option 3. When discussing the history of the United Nations the topic is best organized by using chronological order. A chronological order is a way of organizing events starting with the earliest and following the order in which they occurred. In history, chronological order is often used as a way of recollecting past information. When knowing in which order different events occurred, the historian will have a better understanding of which were the causes and the effects of specific moments in time. When discussing or studying the history of the United Nations, it is important to recollect all the information about the organization based on what happened and when, using chronological order.