Question: What is the county that contains the place of birth for Dennis Gibson?

full_context: Document 1: Elvis Grbac: Although Grbac initially wished to continue his football career at Ohio State, he changed his mind when the Buckeyes fired head coach Earl Bruce and opted instead to join Howard at the University of Michigan, where he played college football from 1989 to 1992. He led the Wolverines to a Gator Bowl in 1991, three Rose Bowls in 1990 and 1993 and 1992 and is best remembered for throwing to wide receiver Desmond Howard during the latter's Heisman-winning season in 1991. In 1991 Grbac's pass to Howard sealed a 24-14 victory over Notre Dame. In that game Grbac completed 20-of-22 passes, a record for a Notre Dame opponent. He finished his career at Michigan as the school's all-time leader in passing attempts (835), completions (522), passing yards (6,460) and passing touchdowns (71). These marks were later broken by John Navarre in 2003 and surpassed by Chad Henne in 2006–2007.
Document 2: Corydon, Iowa: Corydon is a city in Wayne County, Iowa, United States. The population was 1,585 in the 2010 census, a decline from 1,591 in the 2000 census. It is the county seat of Wayne County.
Document 3: Gary Reasons: Gary Phillip Reasons (born February 18, 1962) is a former American football linebacker for the New York Giants of the National Football League, winning Super Bowl XXI and Super Bowl XXV as a member of the team.
Document 4: Derrick Gibson: Derrick Gibson (born March 22, 1979 in Miami, Florida) is a former American football safety who played his entire career for the Oakland Raiders. He was drafted by the Raiders in the first round (28th overall) in the 2001 NFL Draft. He played college football at Florida State.
Document 5: Kalona, Iowa: Kalona is a city in Washington County, Iowa, United States. It is part of the Iowa City, Iowa Metropolitan Statistical Area. The population was 2,363 at the 2010 census. Kalona is the second largest city in Washington County.
Document 6: Des Moines metropolitan area: The Des Moines metropolitan area, officially known as the Des Moines -- West Des Moines, IA Metropolitan Statistical Area (MSA), consists of five counties in central Iowa, United States: Polk, Dallas, Warren, Madison, and Guthrie. The 2010 census population of these counties was 569,633, and the 2017 estimated population was 645,911.
Document 7: Indianola, Iowa: Indianola is a city in Warren County, Iowa, United States, 18 miles south of Des Moines, Iowa. The population was 14,782 at the 2010 census. It is the county seat of Warren County.
Document 8: Chicago Bears: Mike Ditka, a tight end for the Bears from 1961 to 1966, was hired to coach the team by George Halas in 1982. His gritty personality earned him the nickname ``Iron Mike ''. In the 1985 season the fire in the Bears -- Packers rivalry was relit when Ditka used 315 pound defensive tackle`` Refrigerator'' Perry as a running back in a touchdown play at Lambeau Field, against the Packers. The Bears won their ninth NFL Championship, first since the AFL - NFL merger, in Super Bowl XX after the 1985 season in which they dominated the NFL with their then - revolutionary 46 defense and a cast of characters that recorded the novelty rap song ``The Super Bowl Shuffle ''. The season was notable in that the Bears had only one loss, the`` unlucky 13th'' game of the season, a Monday night affair in which they were defeated by the Miami Dolphins. At the time, much was made of the fact that the 1972 Dolphins were the only franchise in history to have had an undefeated season and post-season. The Dolphins came close to setting up a rematch in the Super Bowl, but lost to the New England Patriots in the AFC title game. ``The Super Bowl Shuffle ''was videotaped the day after that Monday night loss in Miami.
Document 9: Middletown, Iowa: Middletown is a city in Des Moines County, Iowa, United States. The population was 318 at the 2010 census. It is part of the Burlington, IA–IL Micropolitan Statistical Area.
Document 10: Barry Sanders: Barry Sanders (born July 16, 1968) is a former American football running back. He played professionally for the Detroit Lions of the National Football League (NFL). A Pro Bowl invitee in each of his ten NFL seasons and two-time NFL Offensive Player of the Year, Sanders led the league in rushing yards four times and established himself as one of the most elusive runners in pro football with his quickness and agility. In 2007, he was ranked by NFL Network's "NFL Top 10" series as the most elusive runner in NFL history, and also topped its list of greatest players never to play in a Super Bowl. He is often regarded as one of the greatest running backs in NFL history.
Document 11: Keith Fahnhorst: Fahnhorst's younger brother Jim Fahnhorst played linebacker in the USFL and for the 49ers from 1984 to 1990. The brothers were teammates on the 1984 49ers team that won Super Bowl XIX and finished with a 15-1 record.
Document 12: Joe Gibson: Billy Joe Gibson (June 28, 1919October 19, 2002) was an American football defensive back and end in the National Football League for the Cleveland Rams (1942, 1944) and the Washington Redskins (1943). Gibson also played in the All-America Football Conference for the Brooklyn Dodgers. He played college football at the University of Tulsa.
Document 13: Saylorville, Iowa: Saylorville is a census-designated place (CDP) in Polk County, Iowa, United States. The population was 3,301 at the 2010 census. It is part of the Des Moines–West Des Moines Metropolitan Statistical Area. The Saydel Community School District is located in this area. The unincorporated community of Marquisville is in this area.
Document 14: Dennis Gibson (American football): Dennis Michael Gibson (born February 8, 1964 in Des Moines, Iowa) is a former American football linebacker who played in the National Football League from 1987-1995 for the Detroit Lions and the San Diego Chargers. Perhaps his most memorable moment came in the , when he sent the Chargers to the Super Bowl by lunging to block a 4th down pass attempt from Pittsburgh Steelers quarterback Neil O'Donnell in the end zone to win the game.
Document 15: Colo, Iowa: Colo is a city in Story County, Iowa, United States. The population was 876 at the 2010 census. It is part of the Ames, Iowa Metropolitan Statistical Area, which is a part of the larger Ames-Boone, Iowa Combined Statistical Area.
ground_truth: Warren County
sub_queries: Dennis Gibson >> place of birth Answer: Des Moines
Des Moines >> located in the administrative territorial entity Answer: Warren County