Context: Bulgaria (tr. '), officially the Republic of Bulgaria (tr. '), is a country in southeastern Europe. It is bordered by Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east. With a territory of , Bulgaria is Europe's 16th-largest country., Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, and the Mediterranean Sea to the south. To the east and southeast, Europe is generally considered as separated from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways of the Turkish Straits. Yet the non-oceanic borders of Europea concept dating back to classical antiquityare arbitrary. The primarily physiographic term "continent" as applied to Europe also incorporates cultural and political elements whose discontinuities are not always reflected by the continent's current overland boundaries., Anatolia (from Greek , '  "east" or "(sun)rise"; in modern ), in geography known as Asia Minor (from '  "small Asia"; in modern ), Asian Turkey, Anatolian peninsula, or Anatolian plateau, is the westernmost protrusion of Asia, which makes up the majority of modern-day Turkey. The region is bounded by the Black Sea to the north, the Mediterranean Sea to the south, and the Aegean Sea to the west. The Sea of Marmara forms a connection between the Black and Aegean Seas through the Bosphorus and Dardanelles straits and separates Anatolia from Thrace on the European mainland., Azerbaijan, officially the Republic of Azerbaijan, is a country in the South Caucasus region, situated at the crossroads of Southwest Asia and Southeastern Europe. It is bounded by the Caspian Sea to the east, Russia to the north, Georgia to the northwest, Armenia to the west and Iran to the south. The exclave of Nakhchivan is bounded by Armenia to the north and east, Iran to the south and west, while having an 8 km border with Turkey in the north west., The Sea of Marmara, also known as the Sea of Marmora or the Marmara Sea, and in the context of classical antiquity as the Propontis, is the inland sea, entirely within the borders of Turkey, that connects the Black Sea to the Aegean Sea, thus separating Turkey's Asian and European parts. The Bosphorus strait connects it to the Black Sea and the Dardanelles strait to the Aegean Sea. The former also separates Istanbul into its Asian and European sides. The sea has an area of 11,350 km² (280 km x 80 km) with the greatest depth reaching ., Adjara, officially known as the Autonomous Republic of Adjara (   ), is a historical, geographic and political-administrative region of Georgia. Located in the country's southwestern corner, Adjara lies on the coast of the Black Sea near the foot of the Lesser Caucasus Mountains, north of Turkey. It is an important tourism destination and includes Georgia's second-largest city of Batumi as its capital. About 350,000 people live on its 2,880 km. , Syria, officially known as the Syrian Arab Republic (""), is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the west, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest. Syria's capital and largest city is Damascus., The Black Sea is a body of water between Eastern Europe and Western Asia, bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. It is supplied by a number of major rivers, such as the Danube, Dnieper, Rioni, Southern Bug, and Dniester. The Black Sea has an area of (not including the Sea of Azov), a maximum depth of , and a volume of . It is constrained by the Pontic Mountains to the south and by the Caucasus Mountains to the east, and features a wide shelf to the northwest. The longest east-west extent is about ., Thrace (Modern , "Thráke" "Trakiya") is a historical and geographic area in southeast Europe, centered on the modern borders of Bulgaria, Greece, and Turkey. In antiquity, it was also referred to as Europe, prior to the extension of the term to describe the whole continent. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east. The areas it comprises are southeastern Bulgaria (Northern Thrace), northeastern Greece (Western Thrace), and the European part of Turkey (Eastern Thrace). The biggest part of Thrace is part of present-day Bulgaria. In Turkey, it is also called Rumeli. The name comes from the Thracians, an ancient Indo-European people inhabiting Southeastern Europe., The Machakhlistskali or Machakhlitskal ( Georgian :  , Turkish : Maçahel Suyu ) is a river that flows from the Artvin Province in Turkey to Adjara autonomous republic of Georgia ., The Aegean Sea  is an elongated embayment of the Mediterranean Sea located between the Greek and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosphorus. The Aegean Islands are within the sea and some bound it on its southern periphery, including Crete and Rhodes., Artvin Province ("Artvinis provintsia") is a province in Turkey, on the Black Sea coast in the north-eastern corner of the country, on the border with Georgia., Western Asia, West Asia, Southwestern Asia or Southwest Asia is the westernmost subregion of Asia. The concept is in limited use, as it significantly overlaps with the Middle East (or Near East), the main difference being the exclusion of Egypt (which would be counted as part of North Africa). The term is sometimes used for the purposes of grouping countries in statistics., The Turkish Straits are a series of internationally-significant waterways in northwestern Turkey that connect the Aegean and Mediterranean seas to the Black Sea., The Mediterranean Sea (pronounced ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant. The sea is sometimes considered a part of the Atlantic Ocean, although it is usually identified as a separate body of water., The Bosphorus (or ) or Bosporus ("Bósporos" ) is a narrow, natural strait and an internationally significant waterway located in northwestern Turkey. It forms part of the continental boundary between Europe and Asia, and separates Asian Turkey from European Turkey. The world's narrowest strait used for international navigation, the Bosphorus connects the Black Sea with the Sea of Marmara, and, by extension via the Dardanelles, the Aegean and Mediterranean Seas., Eurasia is the combined continental landmass of Europe and Asia. The term is a portmanteau of its constituent continents. Located primarily in the Northern and Eastern Hemispheres, it is bordered by the Atlantic Ocean to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two different continents is a historical and cultural construct, with no clear physical separation between them; thus, in some parts of the world, Eurasia is recognized as the largest of five or six continents. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on the paleomagnet data., Turkey, officially the Republic of Turkey (Turkish: ), is a transcontinental country in Eurasia, mainly in Anatolia in Western Asia, with a smaller portion on the Balkan peninsula in Southeast Europe. Turkey is a democratic, secular, unitary, parliamentary republic with a diverse cultural heritage. Turkey is bordered by eight countries: Greece to the west; Bulgaria to the northwest; Georgia to the northeast; Armenia, the Azerbaijani exclave of Nakhchivan and Iran to the east; and Iraq and Syria to the south. The Aegean Sea is to the west, the Black Sea to the north, and the Mediterranean Sea to the south. The Bosphorus, the Sea of Marmara, and the Dardanelles, which together form the Turkish Straits, divide Thrace and Anatolia; they also separate Europe and Asia. Turkey's location has given it geopolitical and strategic importance throughout history., Iran (, also , ; ' ), also known as Persia, officially the Islamic Republic of Iran (' ), is a sovereign state in Western Asia. It is bordered to the northwest by Armenia, the "de facto" Nagorno-Karabakh Republic, and Azerbaijan; to the north by the Caspian Sea; to the northeast by Turkmenistan; to the east by Afghanistan and Pakistan; to the south by the Persian Gulf and the Gulf of Oman; and to the west by Turkey and Iraq. Comprising a land area of , it is the second-largest country in the Middle East and the 18th-largest in the world. With 82.8 million inhabitants, Iran is the world's 17th-most-populous country. It is the only country with both a Caspian Sea and an Indian Ocean coastline. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, make it of great geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic center., Iraq (, or ; '; '), officially known as the Republic of Iraq ('; ') is a country in Western Asia, bordered by Turkey to the north, Iran to the east, Kuwait to the southeast, Saudi Arabia to the south, Jordan to the southwest, and Syria to the west. The capital, and largest city, is Baghdad. The main ethnic groups are Arabs and Kurds; others include Assyrians, Turkmen, Shabakis, Yazidis, Armenians, Mandeans, Circassians, and Kawliya. Around 95% of the country's 36 million citizens are Muslims, with Christianity, Yarsan, Yezidism, and Mandeanism also present. The official languages of Iraq are Arabic and Kurdish., Artvin is a city in northeastern Turkey about 30 km inland from the Black Sea. It is located on a hill overlooking the Çoruh River near the Deriner Dam. It is home of Artvin Çoruh University., Batumi is the second largest city of Georgia, located on the coast of the Black Sea in the country's southwest. Situated in a subtropical zone near the foot of the Lesser Caucasus Mountains, Batumi is a popular tourist destination known for its varying weatherit is a bustling seaside resort during warm seasons, but can get entirely covered in snow during winter. Much of Batumi's economy revolves around tourism and gambling, but the city is also an important sea port and includes industries like shipbuilding, food processing and light manufacturing. Since 2010, Batumi has been transformed by the construction of modern high-rise buildings, as well as the restoration of classical 19th-century edifices lining its historic Old Town., The Dardanelles, also known in Classical Antiquity as the Hellespont
("Hellespontos", literally "Sea of Helle"), is a narrow, natural strait and internationally-significant waterway in northwestern Turkey that forms part of the continental boundary between Europe and Asia, and separates Asian Turkey from European Turkey. One of the world's narrowest straits used for international navigation, the Dardanelles connects the Sea of Marmara with the Aegean and Mediterranean Seas, while also allowing passage to the Black Sea by extension via the Bosphorus., Subject: machakhlistskali, Relation: mouth_of_the_watercourse, Options: (A) arctic ocean (B) atlantic ocean (C) black sea (D) caspian sea (E) dardanelles (F) indian ocean (G) main (H) pacific ocean (I) persian gulf (J) rioni (K) sea (L) sea of marmara (M) southern bug (N) ural river (O) çoruh river
Output: çoruh river