Which is NOT a key area of focus for the UN?

The correct choice is sports development, as it is not one of the primary areas of focus for the United Nations. The UN primarily concentrates on issues that have a significant impact on global peace, security, and development.

Human rights is a core aspect of the UN's mission, aiming to promote and protect fundamental rights and freedoms for all individuals regardless of nationality or background. International security is another vital area where the UN plays a key role, working to prevent conflicts, maintain peace, and promote stability among nations. Sustainable development is also a critical focus, encapsulated in the Sustainable Development Goals (SDGs) that aim to address various global challenges such as poverty, inequality, and climate change.

While sports can play a role in promoting health, cooperation, and peace, it is not a central focus or program area of the UN as compared to the other listed topics. Hence, sports development does not align with the UN's primary objectives.