Explanation
Pair 1 is correctly matched: The Adriatic Sea is a body of water separating the Italian Peninsula from the Balkan peninsula. The countries with coasts on the Adriatic sea are Albania, Bosnia and Herzegovina, Croatia, Italy, Montenegro and Slovenia.
Pair 2 is incorrectly matched: Black Sea is not bordered by Croatia. Black Sea is a large inland sea situated at the southeastern extremity of Europe. It is bordered by Ukraine to the north, Russia to the northeast, Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west.
Pair 3 is correctly matched: Caspian Sea is the world’s largest inland body of water, variously classed as the world’s largest lake or a full-fledged sea. It is an endorheic basin (a basin without outflows) located between Europe and Asia. It is bounded by Kazakhstan in the northeast, Russia in the northwest, Azerbaijan in the west, Iran in the south and Turkmenistan in the southeast.
Pair 4 is correctly matched: The Mediterranean Sea is an intercontinental sea that stretches from the Atlantic Ocean on the west to Asia in the east and separates Europe from Africa. The countries surrounding the Mediterranean in clockwise order: Spain, France, Monaco, Italy, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Albania, Greece, Turkey, Syria, Lebanon, Israel, Egypt, Libya, Tunisia, Algeria, and Morocco.
Pair 5 is incorrectly matched: Red Sea is a narrow strip of water extending south-eastward from Suez, Egypt to the Bab-el-Mandeb Strait. It further connects with the Gulf of Aden and the Arabian Sea. The six countries bordering the Red Sea: Saudi Arabia, Yemen, Egypt, Sudan, Eritrea and Djibouti. The Red Sea is not bordered by Syria.