Answer the following question: Information: - Korea Railroad Corporation (Korean: , Hanja: ), promoted as Korail (), is the national railroad operator in South Korea. - Seoul () officially the Seoul Special City is the capital and largest metropolis of the Republic of Korea (commonly known as South Korea), forming the heart of the Seoul Capital Area, which includes the surrounding Incheon metropolis and Gyeonggi province, the world's 16th largest city. It is home to over half of all South Koreans along with 678,102 international residents. - Siheung is a city in Gyeonggi Province, South Korea. - Gunpo (), formerly romanized as Kunp'o, is a small city in South Korea's Gyeonggi Province, located south of Seoul in the Seoul National Capital Area. It borders Anyang to the north, Uiwang to the east, and Ansan to the south and west, and is connected to its neighbors and to Seoul by lines 1 and 4 of the Seoul Metropolitan Subway. Gunpo is also home to three stops on the Gyeongbu Line, a national railway that links it to the rest of the country. Although 73.2% of the city is greenspace, owing largely to Surisan and various smaller mountains, Gunpo is home to over 286,000 residents in several urban areas. The city's downtown core is Sanbon New Town, a commercial hub which centers on a pedestrian "street of culture" that Gunpo has designated as one of its eight scenic locations. - Gyeonggi-do (Hangul: ) is the most populous province in South Korea. Its name, "Gyeonggi" means "the area surrounding capital". Thus "Gyeonggi-do" can be translated as "province surrounding Seoul". The provincial capital is Suwon. SeoulSouth Korea's largest city and national capitalis in the heart of the province but has been separately administered as a provincial-level "special city" since 1946. IncheonSouth Korea's third largest cityis on the coast of the province and has been similarly administered as a provincial-level "metropolitan city" since 1981. The three jurisdictions collectively cover 11,730km, with a combined population of 25.6 millionamounting to over half of the entire population of South Korea. - The Suin Line (Suwon-Incheon) is a metro line of the Seoul Metropolitan Subway serving the Seoul Capital Area. - South Korea, officially the Republic of Korea (ROK), is a sovereign state in East Asia, constituting the southern part of the Korean Peninsula. - The Gyeongbu Line ("Gyeongbuseon") is the most important railway line in South Korea and one of the oldest. Constructed in 1905, connecting Seoul to Suwon, Daejeon, Daegu, and Busan. The Gyeongbu Line is by far the most heavily travelled rail line in South Korea. High-speed, express, local, and freight trains provide frequent service along its entire length. - Incheon (formerly romanized as Inchon; literally "kind river"), officially the Incheon Metropolitan City(), is a city located in northwestern South Korea, bordering Seoul and Gyeonggi to the east. Inhabited since the New Stone Age, Incheon was home to just 4,700 people when it became an international port in 1883. Today, about 3 million people live in the city, making it Koreas third most populous city after Seoul and Busan. The city's growth has been assured in modern times with the development of its port due to its natural advantages as a coastal city and its proximity to the South Korean capital. It is part of the Seoul Capital Area, along with Seoul itself and Gyeonggi Province, forming the world's second largest metropolitan area by population. - Seoul Metro (Hangul: ) is a public corporation owned by Seoul Metropolitan Government, and one of the major operators of Seoul Metropolitan Subway with Seoul Metropolitan Rapid Transit Corporation and Korail. - The Seoul Metropolitan Subway is an integrated urban rail transit system consisting of 20 rapid transit, light metro, commuter rail and people mover lines located in South Korea. The system serves most of the Seoul Metropolitan Area including the Incheon metropolis and satellite cities in Gyeonggi province. Some lines in the network cross large rural areas to reach major cities in northern Chungnam province and western Gangwon province that lie over 100km away from the capital. - Ansan Line is a railway line connecting Gunpo to Siheung and a line of the Rapid transit in South Korea . The line is also operated by Seoul Metropolitan Subway and is also a part of Seoul Metro 's Line 4 . The section Hanyang Univ. ( Ansan ) -- Oido is the common section with the Suin Line . - Seoul Metropolitan Rapid Transit Corporation (SMRT) was established in 1994 to operate the Seoul Subway lines 5, 6, 7, 8 in Seoul, South Korea. Given the information above, choose from the list below the object entity that exhibits the relation 'operator' with the subject 'ansan line'. Choices: - incheon - korail - seoul metro - seoul metropolitan rapid transit corporation - southern - suwon
Answer:
korail