Which of the following is not a member state of the United Nations (UNO)?

Introduction / Context:
The United Nations has almost universal membership of sovereign states. A few entities, however, are not full member states. Recognising which territories or states are members and which are not is an essential part of international organisation related general knowledge.

Given Data / Assumptions:

• The institution is the United Nations (UNO).
• The options are North Korea, Vatican City, “Vatinum” and Afghanistan.
• “Vatinum” appears to be a misspelling or a fictitious entry used as a distractor.
• The question asks which is not a member state of the UN.

Concept / Approach:
North Korea (Democratic People's Republic of Korea) is a member of the United Nations. Afghanistan is also a UN member. Vatican City, officially the Holy See, has permanent observer status at the UN but is not a full member state, and exam questions usually treat Vatican City as “not a member of UNO”. A fictitious or misspelled name like “Vatinum” does not correspond to a recognised sovereign state and is generally not the intended answer in classic question banks, which emphasise the unique position of Vatican City.

Step-by-Step Solution:
Step 1: Confirm that North Korea is a UN member; it joined in 1991 along with South Korea.Step 2: Recall that Afghanistan has long held membership in the United Nations.Step 3: Understand that Vatican City, represented internationally by the Holy See, is a permanent observer at the UN and not a full UN member state.Step 4: Recognise that “Vatinum” is not the standard spelling of any UN member; it is likely a distractor and not the conceptual focus of the question.Step 5: Since the classic exam fact is that Vatican City is not a UN member, select “Vatican City” as the correct answer.

Verification / Alternative check:
Standard general knowledge sources explicitly note that almost all countries are members of the United Nations, except Vatican City, which has chosen observer status. Therefore, when a list includes North Korea, Afghanistan and Vatican City, the clearly intended correct response to “not a UNO member” is Vatican City, irrespective of the additional fictitious name.

Why Other Options Are Wrong:
North Korea: A recognised member state of the UN since 1991.

Vatinum: This does not correspond to a real UN member or widely recognised state; it is best seen as a typographical or fictional distractor rather than the conceptual answer.

Afghanistan: A long standing member of the UN and actively involved in its work.

Common Pitfalls:
Some candidates may be tempted to select “Vatinum” simply because it looks unfamiliar. However, exam questions typically aim to test knowledge of real entities such as Vatican City, whose special observer status is a classic fact. Another pitfall is assuming North Korea might be excluded because of political tensions, but it is actually a UN member.

Final Answer:
The entity listed that is not a member state of the United Nations is Vatican City.