Which one of the following countries has an unwritten constitution?

The country that has an unwritten constitution is Great Britain. The UK's constitution is not contained in a single written document, but rather is made up of various sources, including statutes, judicial decisions, and conventions. The UK's constitution is known as an unwritten constitution because it does not exist in a single document, like the United States Constitution or the French Constitution. Instead, it is made up of a collection of legal documents, court decisions, and conventions that have evolved over time. Some of the key elements of the UK's unwritten constitution include the Magna Carta, the Bill of Rights, and the Parliament Acts. These documents, along with other legal decisions and conventions, set out the structure and functions of the government, including the roles of the monarch, the Prime Minister, and Parliament. Despite not having a single written document, the UK's constitution is still considered to be a strong and effective system of government that has stood the test of time.