Which organization works closely with NATO to address security needs in Europe?

The United States European Command (USEUCOM) is the correct choice because it is specifically tasked with overseeing military operations and security assistance in Europe, which aligns closely with NATO's focus on collective defense and security in the region. USEUCOM's main responsibility is to support and enhance NATO operations, ensuring that the military strategies and operations are effectively coordinated among member nations.

In contrast, the other commands—United States Central Command, United States Africa Command, and United States Indo-Pacific Command—are focused on different geographic areas that do not directly align with European security concerns. Central Command focuses on the Middle East and parts of Asia, Africa Command on the African continent, and Indo-Pacific Command on the Asia-Pacific region. Each of these commands has distinct operational focuses that do not involve the overarching security needs of Europe in collaboration with NATO. Therefore, USEUCOM is positioned as a key partner to NATO in addressing security challenges within Europe.