The correct answer is - C.) were admitted to the European Union in 2004.
The three Baltic states, Lithuania, Latvia, and Estonia, were all admitted together as a package in the European Union in 2004. These three countries were part of the Soviet Union. Once they gained independence at the begging of the 90's, they started to change dramatically, especially in the economy and the politics. All of them were pro-Western countries, and all of them had big fears that Russia, once consolidated, may try to attack and annex them. Because of this, they did their best to develop in accordance to the Western standards as quickly as possible so that they can become part of the great and stronger unions, such as the European Union and NATO, and they indeed managed to do it, and are part of both.
