Correct Answer:
(b) Only four
Explanation of the Correct Answer:
Out of the six countries listed, the following four are members of NATO (North Atlantic Treaty Organization):
- Bulgaria – Member since 2004
- Croatia – Member since 2009
- North Macedonia – Member since 2020
- Serbia – Not a member, but has observer/partnership status.
- Austria – Not a member, maintains military neutrality.
- Sweden – Joined NATO on March 7, 2024.
Note: As of now (2025), Sweden is a member, which brings the total to four NATO members among the six listed.
Why Other Options Are Incorrect:
- (a) Only three – Incorrect; there are four members, not three.
- (c) Only five – Incorrect; Austria and Serbia are not NATO members.
- (d) All the six – Incorrect; Austria and Serbia are explicitly not members.
Relevant Supplementary Information:
Table: NATO Membership Status of Listed Countries
| Country | NATO Member? | Year of Joining / Status |
|---|
| Austria | No | Neutral since 1955; not a NATO member |
| Bulgaria | Yes | Joined in 2004 |
| Croatia | Yes | Joined in 2009 |
| Serbia | No | Military neutral; member of Partnership for Peace, not NATO |
| Sweden | Yes | Joined NATO in 2024 |
| North Macedonia | Yes | Joined in 2020 |
Related Concepts:
- NATO: A political and military alliance of 32 countries (as of 2025) committed to mutual defense.
- Partnership for Peace (PfP): A NATO program allowing non-member countries like Serbia to engage in limited cooperation.
- Military Neutrality: A stance adopted by countries like Austria, refraining from joining military alliances like NATO.
Current Relevance:
- Sweden’s NATO accession in 2024 followed Finland’s entry in 2023, driven by Russia’s invasion of Ukraine in 2022.
- The expansion of NATO in Eastern Europe remains a geopolitical flashpoint between the West and Russia.
Table: NATO Membership and Related Policies (As of 2025)
| Country | NATO Member? | Year Joined / Status | Military Alignment / Notes |
|---|
| Austria | No | Not a member | Military neutrality since 1955 (enshrined in constitution); not part of NATO or PfP |
| Bulgaria | Yes | Joined in 2004 | Full NATO member; part of NATO’s post-2004 Eastern enlargement |
| Croatia | Yes | Joined in 2009 | Active NATO participant; joined with Albania |
| Serbia | No | Not a member | Maintains military neutrality; member of Partnership for Peace (PfP); historical ties with Russia |
| Sweden | Yes | Joined in March 2024 | Long-time neutral country; joined NATO after Russia’s Ukraine invasion shifted security posture |
| North Macedonia | Yes | Joined in 2020 | Small Balkan state; accession supported by USA and NATO post-name dispute resolution with Greece |
Related Concepts & Context
| Concept | Explanation |
|---|
| NATO (North Atlantic Treaty Organization) | Founded in 1949; now 32 members; mutual defense clause (Article 5); aimed at collective security |
| Partnership for Peace (PfP) | NATO outreach program for non-members like Serbia; allows limited cooperation without full membership |
| Military Neutrality | Policy of non-alignment (Austria, Serbia); avoids formal military alliances |
| Post-1999 NATO Expansion | Included Eastern European and Balkan states like Poland, Romania, Croatia, and North Macedonia |
| Nordic Expansion (2023–24) | Finland (2023) and Sweden (2024) joined NATO in response to Russia’s aggression in Ukraine |
Table: NATO Member Countries (As of 2025)
| Country | Year Joined | Region |
|---|
| Belgium | 1949 | Western Europe |
| Canada | 1949 | North America |
| Denmark | 1949 | Northern Europe |
| France | 1949 | Western Europe |
| Iceland | 1949 | Northern Europe |
| Italy | 1949 | Southern Europe |
| Luxembourg | 1949 | Western Europe |
| Netherlands | 1949 | Western Europe |
| Norway | 1949 | Northern Europe |
| Portugal | 1949 | Southern Europe |
| United Kingdom | 1949 | Western Europe |
| United States | 1949 | North America |
| Greece | 1952 | Southern Europe |
| Türkiye (Turkey) | 1952 | Eurasia (Transcontinental) |
| Germany (West, then Unified) | 1955 | Central Europe |
| Spain | 1982 | Southern Europe |
| Czech Republic | 1999 | Central Europe |
| Hungary | 1999 | Central Europe |
| Poland | 1999 | Central Europe |
| Bulgaria | 2004 | Eastern Europe |
| Estonia | 2004 | Northern Europe (Baltics) |
| Latvia | 2004 | Northern Europe (Baltics) |
| Lithuania | 2004 | Northern Europe (Baltics) |
| Romania | 2004 | Eastern Europe |
| Slovakia | 2004 | Central Europe |
| Slovenia | 2004 | Southern Europe (Balkans) |
| Albania | 2009 | Southern Europe (Balkans) |
| Croatia | 2009 | Southern Europe (Balkans) |
| Montenegro | 2017 | Southern Europe (Balkans) |
| North Macedonia | 2020 | Southern Europe (Balkans) |
| Finland | 2023 | Northern Europe |
| Sweden | 2024 | Northern Europe |
Summary by Region
| Region | Number of Members |
|---|
| Western Europe | 6 |
| Northern Europe | 9 |
| Southern Europe | 10 |
| Central Europe | 5 |
| Eastern Europe | 3 |
| North America | 2 |
| Balkans (subset) | 6 |