Which of these countries was once NOT part Yugoslavia FYRMacedonia Slovenia or Slovakia?

Yugoslavia was a country in Europe that existed from 1918 to 1992. It was composed of six republics: Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia.

FYR Macedonia is the former Yugoslav Republic of Macedonia, which is now an independent country. Slovenia is also a former Yugoslav republic that is now independent. Slovakia is a country in Central Europe that was part of Czechoslovakia until 1993.