Question: Baker Reagan Mayfield, is a college American football quarterback for the Oklahoma Sooners, after sitting out the 2014 season due to NCAA transfer rules, Mayfield won the starting quarterback job in 2015 over which incumbent starter, an American football quarterback for the Atlanta Falcons of the National Football League (NFL)?

Context paragraphs:
Connor Cook: Connor Cook (born January 29, 1993) is an American football quarterback for the Oakland Raiders of the National Football League (NFL).  He played college football for the Michigan State Spartans and was their starting quarterback from 2013 to 2015.  He holds the record for most career wins at Michigan State.  Cook was selected in the fourth round of the 2016 NFL Draft by the Oakland Raiders.  After initially serving as the third-string backup to Derek Carr and Matt McGloin, Cook played in his first NFL game in the Raiders' last regular season game of the 2016 NFL season after Carr and McGloin suffered injuries.  Following this, he was named the starter for the Raiders' playoff game against the Houston Texans and became the first quarterback in NFL history to make his first career start in a playoff game.

Rick Clausen: Richard James Clausen (born June 29, 1982) is the current offensive coordinator/quarterbacks coach at Calabasas High School.  He is also a former American football player who played college football for Louisiana State University and University of Tennessee.  During his two years at LSU (2001 Redshirt and 2002), he played in three games, starting the 2002 game against Ole Miss.  At the end of the 2002 season, he transferred to Tennessee, where he walked on to the football team as a backup quarterback, sitting out the 2003 season under the NCAA transfer rules.  His older brother, Casey, also played college football for Tennessee in 2000-2003 and is the head football coach at Calabasas High School.  His youngest brother, Jimmy, formerly played quarterback for the Baltimore Ravens of the NFL.

Jon Beutjer: Jon Beutjer (born August 15, 1980) is a former American football quarterback.  As a senior at Wheaton Warrenville South High School he threw for a then-national high school record of 60 touchdowns in a 14-game season, winning several Illinois High School Player of the Year honors in the process.  He began his college football career at the University of Iowa, ending Iowa's 19-game losing streak with a victory over Michigan State in his first collegiate start during the 2000 season.  He passed for 390 yards and scored 4 touchdowns against the Spartans.  Throughout his first season campaign with the Hawkeyes, Beutjer could not overcome crowd assaults throughout many games.  Most notably ESPN reported rowdy Wisconsin fans chanting "the future is Beutjer" and "Back to the Beutjer".  He could not shake this and fell to the Badgers that day.  Beutjer joined the Iowa basketball team as a walk-on, seeing very limited action in six games during the 2000-01 season.  During the summer of 2001, Beutjer with roommate and fellow football teammate Sam Aiello got in a dispute over a cable bill, which resulted in Beutjer being knocked unconscious in a parking lot requiring three of his teammates to pull Aiello off of the unconscious Beutjer.  Beutjer loved Iowa and his teammates, but was forced into making a very difficult decision and he wound up transferring to the University of Illinois at Urbana-Champaign.  After sitting out the 2001 season per NCAA transfer rules, he started for the Illini during the 2002 and 2003 seasons.  He was granted a 6th year of eligibility in 2004, where he split playing time with sophomore Brad Bower.  After finishing his college football career, Beutjer played in the Arena Football League and Canadian Football League.

Tyrod Taylor: Tyrod Di'allo Taylor (born August 3, 1989) is an American football quarterback for the Buffalo Bills of the National Football League (NFL).  He was the starting quarterback for the Virginia Tech Hokies football team from the start of the 2008 college football season through the 2011 Orange Bowl, the final game of the 2010 college football season for Virginia Tech.  He was drafted by the Baltimore Ravens in the sixth round of the 2011 NFL Draft and served as the backup to starting quarterback Joe Flacco, including during the Ravens' Super Bowl XLVII victory over the San Francisco 49ers.  Signed by Buffalo as a free agent in 2015, Taylor was named the starting quarterback for the Bills at the beginning of the 2015 NFL season.

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.

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.

Kim McQuilken: Kim Evan McQuilken (born February 26, 1951) is a former American football quarterback in the National Football League for the Atlanta Falcons and Washington Redskins.  He played college football at Lehigh University and was a consensus first team All American and lead the nation in passing in Division II his senior year.  Following his college career McQuilken was drafted in the third round of the 1974 NFL Draft.  Following his seven years in the NFL, he played for one season with the Washington Federals of the United States Football League in their 1983 inaugural season and was their opening day starter.

Cardale Jones: Cardale Jones ( ; born September 29, 1992) is an American football quarterback for the Los Angeles Chargers of the National Football League (NFL).  He played college football at Ohio State.  At the beginning of the 2014 season, Jones was listed as third on the Ohio State depth chart at quarterback.  He ended up as the starter after injuries to Braxton Miller in August and J. T. Barrett in November.  That year, he was the starter for the Buckeyes in the College Football Playoff National Championship.  Jones was drafted by the Buffalo Bills in the fourth round of the 2016 NFL Draft.

Brett Nottingham: Brett Paul Nottingham (born September 13, 1991) is a former American football quarterback.  Nottingham originally committed to UCLA before committing to Stanford.  Nottingham competed with Josh Nunes for the starting quarterback job, and Nunes would be named the starter.

Michael Vick: Michael Dwayne Vick (born June 26, 1980) is a former American football quarterback who played 13 seasons in the National Football League, primarily with the Atlanta Falcons and the Philadelphia Eagles.  He played college football at Virginia Tech and was selected by the Falcons as the first overall pick in the 2001 NFL Draft.  During his six years with the Falcons, Vick was regarded as having transformed the quarterback position with his rushing abilities and was named to three Pro Bowls.  He holds the record for the most career rushing yards by a quarterback (6,109) and the most rushing yards by a quarterback in a season (1,039).

Supporting paragraphs: Baker Mayfield Trevor Knight
Answer: Trevor Knight