Question: Who was Baker Mayfield's football coach in 2015?

full_context: Document 1: Clayton Thorson: Clayton James Thorson is an American football quarterback. He is currently a redshirt junior and the starting quarterback for the 2017 Northwestern Wildcats football team. After redshirting in 2014, he was named the starting quarterback in 2015 and led the Wildcats to the third 10-win season in program history. As a starter for the 2016 team, he earned Academic All-Big Ten honors. Thorson was selected by ESPN.com as the seventh best high school quarterback and played in the 2014 Semper Fidelis All-American Bowl.
Document 2: Trevor Knight: Trevor Knight (born October 3, 1993) is an American football quarterback for the Atlanta Falcons of the National Football League (NFL). He played college football for the Oklahoma Sooners and Texas A&M Aggies. After leading Oklahoma to an 8–5 record in the 2014 season, he lost the starting job in an open quarterback competition to Texas Tech transfer Baker Mayfield prior to the 2015 season. On January 4, 2016, it was announced that Knight would transfer to Texas A&M University.
Document 3: Baker Mayfield: Baker Reagan Mayfield (born April 14, 1995) is a college American football quarterback for the Oklahoma Sooners. Mayfield began his college football career as a walk-on player for the Texas Tech Red Raiders. He is notable for being the first walk-on true freshman quarterback to start a season opener at a BCS school. Mayfield transferred from Texas Tech to Oklahoma following alleged scholarship issues and a lack of communication with coaches. After sitting out the 2014 season due to NCAA transfer rules, Mayfield won the starting quarterback job in 2015 over Cody Thomas and incumbent starter Trevor Knight.
Document 4: 2015 Oklahoma Sooners football team: The 2015 Oklahoma Sooners football team represented the University of Oklahoma in the 2015 NCAA Division I FBS football season, the 121st season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 17th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 5: Jameis Winston: Jameis Lanaed Winston ( , , born January 6, 1994) is an American football quarterback for the Tampa Bay Buccaneers of the National Football League (NFL). Born and raised in Alabama, he was a highly regarded quarterback in high school, and led his team to the state championship as a junior. Winston played college football for the Florida State Seminoles and as a Redshirt freshman became the youngest player to win the Heisman Trophy and helped lead the Seminoles to a victory in the 2014 BCS National Championship Game. In his sophomore and final year, the Seminoles advanced to the Rose Bowl, part of the College Football Playoff. Winston also played on Florida State's baseball team. Winston was drafted as the first overall pick by the Buccaneers in the 2015 NFL Draft.
Document 6: Matt McGloin: Matthew James McGloin (born December 2, 1989) is an American football quarterback who is currently a free agent. He was the starting quarterback for the Penn State Nittany Lions football team from 2010 to 2012. He is the first walk-on quarterback to start at Penn State since scholarships were reinstated in 1949. Prior to his college career, McGloin was a Pennsylvania all-state quarterback while attending West Scranton High School.
Document 7: Case McCoy: Casey Burl "Case" McCoy (born February 12, 1990) is a former American football quarterback for the University of Texas Longhorns football team. He started 16 games for Texas over a three-year period, amassing a 9–7 record. He is also known as the younger brother of NFL quarterback Colt McCoy.
Document 8: 2016 Oklahoma Sooners football team: The 2016 Oklahoma Sooners football team represented the University of Oklahoma in the 2016 NCAA Division I FBS football season, the 122nd season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 18th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They are a charter member of the Big 12 Conference.
Document 9: Todd Reesing: Todd Reesing (born September 20, 1987) is a former American football quarterback. He played in college at the University of Kansas. After graduating from Kansas, he briefly spent time with the Saskatchewan Roughriders of the Canadian Football League during their 2010 off-season. After his career was over, he began doing color commentary for the Jayhawk Television Network. Reesing led the Jayhawks to their best start in school history, winning their first 11 games of the 2007 season. The Jayhawks finished the season 12–1 and won the 2008 Orange Bowl, the schools first and only BCS Bowl victory. Reesing owns Kansas career passing records in several categories, passing yards, passing touchdowns, quarterback rating (minimum 200 attempts), completions, attempts, and completion percentage (minimum 200 attempts), as well as single game records for passing yards and passing touchdowns.
Document 10: Matt Barkley: Matthew Montgomery Barkley (born September 8, 1990) is an American football quarterback who is currently a free agent. He played college football at USC, and was drafted by the Philadelphia Eagles in the fourth round of the 2013 NFL Draft. Barkley has also played for the Arizona Cardinals, Chicago Bears and San Francisco 49ers.
Document 11: 2005 Oklahoma Sooners football team: The 2005 Oklahoma Sooners football team represented the University of Oklahoma in the 2005 NCAA Division I-A football season, the 111th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his seventh season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 12: 2014 Oklahoma Sooners football team: The 2014 Oklahoma Sooners football team represented the University of Oklahoma in the 2014 NCAA Division I FBS football season, the 120th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 16th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a member of the Big 12 Conference.
Document 13: 2013 Oklahoma Sooners football team: The 2013 Oklahoma Sooners football team represented the University of Oklahoma in the 2013 NCAA Division I FBS football season, the 119th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 15th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 14: 2010 Oklahoma Sooners football team: The 2010 Oklahoma Sooners football team represented the University of Oklahoma in the 2010 NCAA Division I FBS football season, the 116th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 12th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 15: 2012 Oklahoma Sooners football team: The 2012 Oklahoma Sooners football team represented the University of Oklahoma in the 2012 NCAA Division I FBS football season, the 118th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 14th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
ground_truth: Bob Stoops