Question: What is the seat of the county in which Walnut Grove, a city in the state where Christina Yang goes in season 9, is located?

full_context: Document 1: Greene County Almshouse: The Greene County Almshouse is a historic poorhouse located in Greene County, Illinois, along a township road northeast of the city of Carrollton. The almshouse was built in 1870 in accordance with an 1839 state law which provided for each county to establish its own almshouse or poor farm for welfare recipients. Prior to passage of the law, public welfare in Illinois had taken the form of "outdoor relief", in which the poor worked on farms in exchange for basic support. Under Illinois' county almshouse system, the poor were intended to receive shelter and necessities in the houses, often in exchange for farm labor on the property. By 1903, all but two of Illinois' counties had established an almshouse or poor farm.
Document 2: Walnut Grove, Minnesota: Walnut Grove, Minnesota City U.S. Post Office, First State Bank Building, and water tower in Walnut Grove Location of Walnut Grove, Minnesota Coordinates: 44 ° 13 ′ 25 ''N 95 ° 28 ′ 8'' W ﻿ / ﻿ 44.22361 ° N 95.46889 ° W ﻿ / 44.22361; - 95.46889 Coordinates: 44 ° 13 ′ 25 ''N 95 ° 28 ′ 8'' W ﻿ / ﻿ 44.22361 ° N 95.46889 ° W ﻿ / 44.22361; - 95.46889 Country United States State Minnesota County Redwood Founded 1874 Incorporated 1879 Area Total 1.06 sq mi (2.75 km) Land 1.06 sq mi (2.75 km) Water 0 sq mi (0 km) Elevation 1,217 ft (371 m) Population (2010) Total 871 Estimate (2016) 813 Density 820 / sq mi (320 / km) Time zone Central (CST) (UTC - 6) Summer (DST) CDT (UTC - 5) ZIP code 56180 Area code (s) 507 FIPS code 27 - 67846 GNIS feature ID 0653743
Document 3: Jackson Avery: In the series 11 finale Kepner tells Avery that she is leaving with Owen Hunt to serve as a trauma surgeon in the Army; it will help her grieve for their son. Avery lets her go and wonders how he can deal with his own grief. After discussions over the phone via Facetime, Kepner tells Avery that she is extending her service time. The sound of gunfire and explosions are heard at April's base camp, leaving her to quickly terminate the call. On Valentine's Day, Kepner returns to the hospital, where she and Avery embrace in the foyer. In season 12, their marriage begins to fall apart and they grow estranged. In episode 11, they file for a civil divorce. After their divorce is completed, Kepner reveals that she is pregnant with Avery's child. In Season 14 Jackson begins a relationship with Maggie Pierce.
Document 4: Redwood, Virginia: Redwood is an unincorporated community in Franklin County, Virginia, United States. Redwood is located on Virginia State Route 40 east-northeast of Rocky Mount. Redwood has a post office with ZIP code 24146, which opened on August 9, 1880. zip is incorrect 24092
Document 5: Flight (Grey's Anatomy): ``Flight ''is the twenty - fourth and final episode of the eighth season of the American television medical drama Grey's Anatomy, and the show's 172nd episode overall. It was written by series creator Shonda Rhimes, and directed by Rob Corn. The episode was originally broadcast on the American Broadcasting Company (ABC) in the United States on May 17, 2012. In the episode, six doctors from Seattle Grace Mercy West Hospital who are victims of an aviation accident fight to stay alive, but Dr. Lexie Grey (Chyler Leigh) ultimately dies. Other storylines occur in Seattle where Dr. Richard Webber (James Pickens, Jr.) plans his annual dinner for the departing residents, Dr. Owen Hunt (Kevin McKidd) fires Dr. Teddy Altman (Kim Raver), and Dr. Miranda Bailey (Chandra Wilson) gets engaged.
Document 6: Walnut Grove, Washington: Walnut Grove is a census-designated place (CDP) in Clark County, Washington, United States. The population was 9,790 at the 2010 census, up from 7,164 at the 2000 census.
Document 7: Red Wing, Minnesota: Red Wing (Formerly Known as Wahcoota) is a city in Goodhue County, Minnesota, United States, along the upper Mississippi River. The population was 16,459 at the 2010 census. It is the county seat of Goodhue County.
Document 8: Lexie Grey: The character's focal storyline involved a romantic relationship with plastic surgeon Mark Sloan (Eric Dane). She sustained life - threatening injuries after an aviation accident, in the eighth - season finale, which ultimately ended in her death. The character's death resulted in mixed critical feedback and the reason given for the departure was Leigh's desire to spend more time with her family. Rhimes has characterized Lexie as being a dork, as well as having issues with saying how she feels. Leigh has been moderately well received by critics, and was among the cast to receive a Screen Actors Guild Award nomination for Outstanding Performance by an Ensemble in a Drama Series in 2007.
Document 9: Grey's Anatomy (season 9): The season follows the characters dealing with the aftermath of the season eight plane crash that claimed the life of Lexie Grey (Chyler Leigh) and upon rescue Mark Sloan (Eric Dane), who dies after sustaining injuries from the crash. Derek Shepherd (Patrick Dempsey) finds his surgical career in doubt after badly damaging his hand but Callie Torres (Sara Ramirez) ultimately manages to save his hand. The show's protagonist Meredith Grey (Ellen Pompeo) deals with the loss of her half - sister Lexie and later discovers that she is pregnant. Cristina Yang (Sandra Oh) who is severely traumatized upon rescue and later decides to take up her fellowship in Minnesota. Arizona Robbins (Jessica Capshaw) another survivor of the plane crash upon return realizes that her leg has to be amputated to save her life, reacts badly to this, becoming bitter and blaming her wife Callie and her former friend Alex Karev (Justin Chambers). To prevent the doctors' court case from being thrown out, Owen Hunt (Kevin McKidd) decides to divorce Yang, but the two agree to start again. The hospital itself becomes liable for the crash, putting its future in extreme doubt prompting the four crash survivors and Torres to purchase the hospital. Miranda Bailey (Chandra Wilson) marries her partner Ben Warren (Jason George), April Kepner (Sarah Drew) returns home to Ohio, but is brought back by Hunt to rejoin the hospital and she restarts her relationship with Jackson Avery (Jesse Williams).
Document 10: Redwood County Poor Farm: The Redwood County Poor Farm (or Poorhouse) was a county run institution serving impoverished and aged people in Redwood Falls, Minnesota, United States, from 1884 to 1889 and again from 1909 to 1967, when it was converted to a nursing home.
Document 11: Meredith Grey: Meredith is widowed when Derek is killed in a car accident and was taken to an understaffed hospital. The doctors failed to recognize his head injury in time and allowed personal conflicts to interfere. Derek is declared brain dead, and Meredith must go to the medical center to consent to remove him from life support, shortly before she's hit with the first waves of morning sickness. She tells Penny, the intern who was assigned to Derek that every doctor has ``that one ''patient who dies on their watch and haunts them forever and`` that one will make you work harder, and they make you better.''
Document 12: Walnut Grove, Minnesota: Walnut Grove is a city in Redwood County, Minnesota, United States. The population was 871 at the 2010 census. Another name formerly associated with the area is Walnut Station.
Document 13: Redwood National and State Parks: In 1850, old-growth redwood forest covered more than 2,000,000 acres (8,100 km2) of the California coast. The northern portion of that area, originally inhabited by Native Americans, attracted many lumbermen and others turned gold miners when a minor gold rush brought them to the region. Failing in efforts to strike it rich in gold, these men turned toward harvesting the giant trees for booming development in San Francisco and other places on the West Coast. After many decades of unrestricted clear-cut logging, serious efforts toward conservation began. By the 1920s the work of the Save the Redwoods League, founded in 1918 to preserve remaining old-growth redwoods, resulted in the establishment of Prairie Creek, Del Norte Coast, and Jedediah Smith Redwoods State Parks among others. Redwood National Park was created in 1968, by which time nearly 90% of the original redwood trees had been logged. The National Park Service (NPS) and the California Department of Parks and Recreation (CDPR) administratively combined Redwood National Park with the three abutting Redwood State Parks in 1994 for the purpose of cooperative forest management and stabilization of forests and watersheds as a single unit.The ecosystem of the RNSP preserves a number of threatened animal species such as the tidewater goby, Chinook salmon, northern spotted owl, and Steller's sea lion. In recognition of the rare ecosystem and cultural history found in the parks, the United Nations designated them a World Heritage Site on September 5, 1980 and part of the California Coast Ranges International Biosphere Reserve on June 30, 1983.
Document 14: Weedpatch Camp: Between April 1935 and December 1936, the federal government's New Deal Resettlement Administration (RA) had relocated many struggling rural and urban families to planned communities. Weedpatch Camp, however, was constructed by the Works Progress Administration. It was located on the outskirts of the small towns of Arvin and Weedpatch. The camp now is located in an unincorporated area of Kern County just south of Bakersfield.
Document 15: Poplar Grove Township, Roseau County, Minnesota: Poplar Grove Township is a township in Roseau County, Minnesota, United States. The population was 80 at the 2000 census.
ground_truth: Redwood Falls
sub_queries: where does christina yang go in season 9 Answer: Minnesota
Walnut Grove, Minnesota >> located in the administrative territorial entity Answer: Redwood County
Redwood County >> capital Answer: Redwood Falls