Who is eligible for membership in the UN?

Membership in the United Nations is specifically designed for peace-loving nations that are willing to accept and abide by the obligations and principles set forth in the UN Charter. This includes a commitment to promote peace, security, and cooperation among nations. By stating that a nation must be peace-loving and accept UN obligations, the focus is on the values and principles that underpin the organization's mission rather than just financial contributions or geographical location.

The other options, while they may seem plausible to a degree, do not encapsulate the criteria for membership as effectively. For instance, merely being willing to pay dues does not ensure that a nation aligns with the UN’s core values. Similarly, restricting membership to only democracies excludes nations that may be peace-loving but do not follow a democratic form of government. Lastly, limiting eligibility to European nations disregards the UN’s global reach and purpose, as the organization is meant to include all member states from around the world, not just those from a specific continent.