BREXIT refers to the Great Britain leaving which one of the following?

BREXIT refers to the Great Britain leaving which one of the following?

International Monetary Fund
Commonwealth
World Trade Organization
European Union
This question was previously asked in
UPSC CDS-1 – 2017
BREXIT is a portmanteau of “British exit” and refers to the United Kingdom’s withdrawal from the European Union. The UK held a referendum on June 23, 2016, where voters decided to leave the EU. The process was formally initiated in March 2017 and the UK officially left the EU on January 31, 2020.
BREXIT specifically denotes the UK’s departure from the European Union.
The European Union (EU) is a political and economic union of member states located primarily in Europe. The withdrawal process was complex and involved negotiations on future relations, including trade. The term BREXIT gained widespread prominence following the 2016 referendum.