Which country has a coastline on the Caspian Sea?

Which country has a coastline on the Adriatic Sea? Which country is home to the world's longest sandy beach? What is the name of the bay that borders the city of Rio de Janeiro? Which of the following countries does not have a coastline on the Baltic Sea? Which of the following countries has a coastline on the Black Sea? Which of the following countries does not have a coastline on the Persian Gulf? Which country has a coastline on the Gulf of Finland? Which country has a coastline on the Black Sea and the Mediterranean Sea?