Which country has the coastline along the Black Sea?

Which country has the shortest coastline in the world? Which country has the coastline along the Adriatic Sea? Which country has a coastline along the Persian Gulf? Which country has a coastline along the Baltic Sea? Which country has the longest coastline in the world? 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?