Question: Which division did Oklahoma City Thunder win in 2015-16, their first season under current head coach Billy Donovan?

Context paragraphs:
List of Oklahoma City Thunder head coaches: The Oklahoma City Thunder is an American professional basketball franchise based in Oklahoma City, Oklahoma.  It plays in the Northwest Division of the Western Conference in the National Basketball Association (NBA).  It was known as the Seattle SuperSonics from 1967 to 2008.  The team plays its home games at the Chesapeake Energy Arena.  As of October 2008, the Thunder is currently owned by Professional Basketball Club LLC and coached by Billy Donovan, with Sam Presti as its general manager.  The team was formed in 1967.  After spending 41 seasons in Seattle, Washington, the SuperSonics moved to Oklahoma City.  Owner Clay Bennett, who purchased the team in 2006, sought to get public funding for a new arena in Seattle, or a major renovation of the KeyArena in 2007.  After failing to do so, he decided to move the team to Oklahoma City.  Seattle sued Bennett's group to enforce the lease that required the team to stay until 2010.  The two sides reached a $45 million settlement to pay off the team's lease with KeyArena in July 2008.

William Donavan III: William Connor Donovan III is an American professional basketball coach for the Austin Spurs.  He is the son of Billy Donovan the head coach for the Oklahoma City Thunder of the National Basketball Association (NBA).

Billy Donovan: William John Donovan Jr. (born May 30, 1965) is an American professional basketball coach who is currently the head coach for the Oklahoma City Thunder of the National Basketball Association (NBA).  He previously spent 19 seasons at the University of Florida, where his Florida Gators teams won back-to-back NCAA championships in 2006 and 2007.  Donovan has more wins than any other coach in the history of the Florida basketball program, and he coached the Gators to more NCAA tournament appearances, NCAA tournament wins, and Southeastern Conference (SEC) championships than all other Florida coaches combined.

2014–15 Florida Gators men's basketball team: The 2014–15 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2014–15 NCAA Division I men's basketball season.  The Gators competed in the Southeastern Conference (SEC).  They were led by nineteen-year head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.  They finished the season 16–17, 8–10 in SEC play to finish in a tie for eighth place.  They advanced to the quarterfinals of the SEC Tournament where they lost to Kentucky.

2010–11 Florida Gators men's basketball team: The 2010–11 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2010–11 college basketball season.  The Gators competed in Division I of the National Collegiate Athletic Association (NCAA) and the Eastern Division of the Southeastern Conference (SEC).  They were led by head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.

2006–07 Florida Gators men's basketball team: The 2006–07 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2006–07 college basketball season.  The Gators competed in Division I of the National Collegiate Athletic Association (NCAA) and the Eastern Division of the Southeastern Conference (SEC).  They were led by head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.

2007–08 Florida Gators men's basketball team: The 2007–08 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2007–08 college basketball season.  The Gators competed in Division I of the National Collegiate Athletic Association (NCAA) and the Eastern Division of the Southeastern Conference (SEC).  They were led by head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.

2000–01 Florida Gators men's basketball team: The 2000–01 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2000–01 college basketball season.  The Gators competed in Division I of the National Collegiate Athletic Association (NCAA) and the Eastern Division of the Southeastern Conference (SEC).  They were led by head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.

2009–10 Florida Gators men's basketball team: The 2009–10 Florida Gators men's basketball team represented the University of Florida in the sport of basketball during the 2009–10 college basketball season.  The Gators competed in Division I of the National Collegiate Athletic Association (NCAA) and the Eastern Division of the Southeastern Conference (SEC).  They were led by head coach Billy Donovan, and played their home games in the O'Connell Center on the university's Gainesville, Florida campus.

2015–16 Oklahoma City Thunder season: The 2015–16 Oklahoma City Thunder season was the 8th season of the franchise in Oklahoma City and the 50th in the National Basketball Association (NBA), and the first under head coach Billy Donovan.  After coming just short of making the playoffs the previous season, the Thunder won the Northwest Division and clinched the third seed in the Western Conference.  The team reached the Western Conference Finals for the fourth time in a span of six seasons, but was eliminated by the Golden State Warriors in seven games after leading the series 3-1.  After the season Kevin Durant left the team in free agency for the Warriors.

Supporting paragraphs: 2015–16 Oklahoma City Thunder season Billy Donovan
Answer: Northwest Division