Which of the following countries is a landlocked country in Southeastern Europe?

What is the currency used in Poland? What is the currency used in South Africa? Which landlocked country is the largest in South America? Which landlocked country is home to the ancient city of Samarkand? What is the world's largest landlocked country? Which landlocked country in Central Asia has the highest population? Which African landlocked country is known for its diamond mining? Which of the following European countries is landlocked?