As of 2022, which of the following countries are in the European Union?

Oh, almost forgot about this Russia and Serbia are both predominantly Slavic and Eastern Orthodox countries, which share a strong mutual cultural affinity. The countries have been close allies for centuries; and the friendship between them has been strongly maintained despite Serbia's recent attempt to maintain closer relations with the West. Basically, Serbia is Pro-Russia

Switzerland always been neutral. Norway is not in the EU due to high membership fee/price. For Iceland, it is not in the EU due to disputes on fisheries, same thing applys to Norway. Serbia is not in the EU due to "close ties" with Russia. After the 2014 annexation of Crimea and the current invasion of Ukraine on 24 February 2022, EU starts to feel like they would not allow Serbia to join EU anymore. Serbia is actually skeptical of joining Western-backed and Western-made alliances due to their bombing of Yugoslavia in 1999. They supported Kosovo which Serbia did not like it and claims it as their own province