Which of the following was not an organization within the League of Nations?

Permanent Central Opium Board is correct answer.Key Points

• The League of Nations was made up of three major organs. The Assembly, in which all member countries were represented on an equal footing; the Council, made up of permanent and non-permanent members; and the Secretariat, which handled day-to-day operations at the League's headquarters in Geneva, Switzerland.
• Permanent Central Opium Board is not an organization within the League of Nations.

Additional Information

• The League of Nations' principal representative body was the Assembly. It was made up of delegates from all Member States, who were all equally represented: each State had one vote, regardless of geography, demographics, or economic status. 
• The League of Nations' primary organs were the General Assembly, the Council, and the Secretariat.
• The General Assembly, which met once a year, was made up of representatives from all member countries and made decisions on the organization's policies.
• The Council consisted of four permanent members (Britain, France, Italy, and Japan) and four (later nine) others elected every three years by the General Assembly.
• The Secretariat created the agenda and produced meeting reports.
• The United Nations General Assembly established the Office of the United Nations High Commissioner for Refugees on December 14, 1950. 
• The agency's mission is to lead and coordinate international action to protect refugees and solve refugee crises around the world.​