Question: Who was the head coach during the 2014 and 2015 season for the Minnesota Vikings?
Context: The Minnesota Vikings season was the franchise's 54th season in the National Football League and the first under head coach Mike Zimmer.  It was the first of two seasons in which the Vikings played at the outdoor TCF Bank Stadium on the campus of the University of Minnesota.  Construction of U.S. Bank Stadium began on the site of the Hubert H. Humphrey Metrodome, with a target of opening for the 2016 season. The 1962 Minnesota Vikings season was the second year of season play for the Minnesota Vikings and the 43rd regular season of the National Football League.  The Vikings finished with a record of two wins, 11 losses, and one tie under head coach Norm Van Brocklin.  The 2-11-1 record still stands as the Vikings' worst season record by terms of winning percentage, both by today's standards (.179) and back then (.154), where ties weren't counted as games played.  The Vikings have won at least three games in every season since. The 2015 season was the Minnesota Vikings' 55th season in the National Football League and their second under head coach Mike Zimmer.  It marked the last season in which the Vikings played their home games at the University of Minnesota's on-campus TCF Bank Stadium, before moving into U.S. Bank Stadium, which is to open in July 2016, located on the site of the now-demolished Hubert H. Humphrey Metrodome.  The Vikings improved on their 7–9 mark from last season and clinched a playoff berth for the first time since 2012.  They also won their first NFC North title since 2009 with a Week 17 victory at the Packers.  As a result, they hosted the Seattle Seahawks in the wild card round of the 2015–16 NFL playoffs, but lost 10–9 after kicker Blair Walsh missed a potential game-winning, 27-yard field goal in the final seconds. Harry Peter "Bud" Grant Jr. (born May 20, 1927) is a former coach and player of American football and Canadian football.  Grant served as the head coach of the Minnesota Vikings of the National Football League (NFL) for eighteen seasons; he was the team's second (1967–83) and fourth (1985) head coach.  Before coaching the Vikings, he was the head coach of the Winnipeg Blue Bombers of the Canadian Football League (CFL) for ten seasons, winning the Grey Cup four times.  Grant is the most successful coach in Vikings history, and the third most successful professional football coach overall (behind Don Shula and George Halas), with a combined 290 wins in the NFL and CFL.  Grant was elected to the Canadian Football Hall of Fame in 1983 and to the Pro Football Hall of Fame in 1994.  He was the first coach in the history of professional football to guide teams to the Grey Cup and the Super Bowl. The Minnesota Vikings season was the sixth year of season play for the Minnesota Vikings and the 47th regular season of the National Football League.  The Vikings finished with a record of four wins, nine losses, and one tie under sixth-year head coach Norm Van Brocklin, who resigned on February 11, 1967. The 1965 Minnesota Vikings season was the fifth year of season play for the Minnesota Vikings and the 46th regular season of the National Football League.  The Vikings finished with a record of seven wins and seven losses under head coach Norm Van Brocklin. The 2007 Minnesota Vikings season was the team's 47th season in the National Football League.  The Vikings' 8–8 record under second-year head coach Brad Childress was an improvement on their 6–10 record in 2006; nonetheless, for the third straight year, the Vikings failed to make the playoffs.  The Vikings also lost both games to the Packers in the 2007 season, making head coach Brad Childress 0–4 against the division rivals from Wisconsin. The 1963 Minnesota Vikings season was the third year of play for the Minnesota Vikings and the 44th regular season of the National Football League.  The Vikings finished with a record of five wins, eight losses, and one tie under head coach Norm Van Brocklin.  Five wins in a season represented the most in the franchise's three-year history.  22-year-old Paul Flatley of Northwestern University was named the NFL's Rookie of the Year, a first for the fledgling franchise. The Minnesota Vikings season was the 37th year of season play for the Minnesota Vikings and the 78th regular season of the National Football League.  The Vikings finished with a record of nine wins and seven losses.  Their record was good enough to qualify for a wild card berth.  In the wild card round against the New York Giants, the Vikings came back from a 22–13 deficit with 90 seconds to play to defeat the Giants 23–22.  It was their first playoff victory since 1988 and their first under head coach Dennis Green.  In the Divisional round, the Vikings were defeated by the San Francisco 49ers, 38–22. The 1964 Minnesota Vikings season was the fourth year of season play for the Minnesota Vikings and the 45th regular season of the National Football League.  The Vikings finished with a record of eight wins, five losses, and one tie under head coach Norm Van Brocklin.  The eight wins was the most at the time in the franchise's four-year history.  To date, this is the only season the Vikings wore white jerseys for their home games.
Answer: Mike Zimmer