Which of the following countries is NOT part of the European Union in 2025?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → United Kingdom
The United Kingdom left the European Union on 31 January 2020, after the 2016 referendum known as Brexit, so it was not a member in 2025. Austria, Denmark and Belgium are all members; Belgium was one of the six founding members, and its capital Brussels hosts the main EU institutions.