Question: Which is city is the county seat of a county with a standard abbreviation of SU?

Context paragraphs:
McPherson County, Kansas: McPherson County (standard abbreviation: MP) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 29,180.  The largest city and county seat is McPherson.  The county is named for Civil War General James B. McPherson.

Lyon County, Kansas: Lyon County (standard abbreviation: LY) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 33,690.  The county seat and largest city is Emporia.  The county was named for General Nathaniel Lyon, who was killed at the Battle of Wilson's Creek in the Civil War.

Meade County, Kansas: Meade County (standard abbreviation: ME) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 4,575.  The largest city and county seat is Meade.  The county was created in 1873 and named in honor of General George G. Meade.

Lane County, Kansas: Lane County (standard abbreviation: LE) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 2,150, making it the third-least populous county in Kansas.  The county seat is Dighton, the only city in the county.  The county was named after James H. Lane who was a leader of the Jayhawker abolitionist movement and served as one of the first U.S. Senators from Kansas.

Wellington, Kansas: Wellington is a city in and the county seat of Sumner County, Kansas, United States.  As of the 2010 census, the city population was 8,172.

Ness County, Kansas: Ness County (standard abbreviation: NS) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 3,107.  The largest city and county seat is Ness City.  The county was named for Corporal Noah V. Ness of the 7th Kansas Cavalry.

Norton County, Kansas: Norton County (standard abbreviation: NT) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 5,671.  The largest city and county seat is Norton.  The county was established in 1867 and named for Orloff Norton, captain of Company L, 15th Kansas Militia Infantry Regiment.

Sumner County, Kansas: Sumner County (standard abbreviation: SU) is a county located in the U.S. state of Kansas.  As of the 2010 census, the population was 24,132.  Its county seat is Wellington.

Scott County, Kansas: Scott County (standard abbreviation: SC) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 4,936.  Its county seat is Scott City, the only city in the county.

Logan County, Kansas: Logan County (standard abbreviation: LG) is a county located in the U.S. state of Kansas.  As of the 2010 census, the county population was 2,756.  The largest city and county seat is Oakley.  The county was named for Gen. John A. Logan.

Supporting paragraphs: Sumner County, Kansas Wellington, Kansas
Answer: Wellington