Question: Which season did Brain Billick coach the Baltimore Ravens though in 2001?

Context:
2001 Baltimore Ravens season
The Baltimore Ravens season was the franchise's 6th season in the National Football League (NFL) and the third under head coach Brian Billick.
Issac Booth
Issac Ramoun Booth (born May 23, 1971) is a former American professional football player who played three seasons in the National Football League with the Cleveland Browns and Baltimore Ravens.
 Booth was drafted by the Browns in the fifth round of the 1994 NFL Draft and played cornerback for the Browns for the 1994 and 1995 seasons, earning one start in each of his first two seasons.
 After the 1995 season the original Cleveland Browns relocated to Baltimore, Maryland and became the Baltimore Ravens.
 Booth played his final season with the Ravens playing in 11 games and earning a career high three starts.
 Booth retired from football after the 1996 season.
 During his brief career, Booth played in 36 games, earning five starts, 55 tackles, two interceptions and one forced fumble.
Brian Billick
Brian Harold Billick (born February 28, 1954) is a former National Football League coach and commentator.
 Billick spent nine seasons as head coach of the Baltimore Ravens from January 19, 1999 to December 31, 2007; he led the Ravens to a 34–7 victory over the New York Giants in Super Bowl XXXV, the franchise's first Super Bowl appearance.
 He was also the offensive coordinator for the Minnesota Vikings (1994–1998) when they broke the scoring record in the 1998 season.
2011 Baltimore Ravens season
The Baltimore Ravens season was the team's 16th in the National Football League and city of Baltimore, and the 14th to host home games at M&T Bank Stadium.
 2011 marked one of the most successful seasons in Baltimore Ravens franchise history.
 The Ravens completed the season with a 12–4 record, matching their record from 2010, and winning the AFC North division title for the third time in franchise history.
 By earning a playoff berth in 2011, the Ravens set a franchise record by going to the postseason for four consecutive seasons.
Herman Arvie
Herman Joseph Arvie (born October 12, 1970) is a retired American professional football player who played four seasons in the National Football League as an offensive tackle with the Cleveland Browns and Baltimore Ravens.
 Arvie was drafted by the Browns out of Grambling State University in the fifth round of the 1993 NFL Draft.
 Arvie played three seasons with the Browns before the franchise moved to Baltimore and became the Baltimore Ravens.
 With the Ravens in 1996, Arvie scored his only touchdown, scoring on a one-yard reception.
 After the 1996 season, Arvie retired from football.
Chris Hewitt
Christopher Horace Hewitt (born July 22, 1974) is a former National Football League defensive back who is currently the secondary coach of the Baltimore Ravens.
 Hewitt played professionally for three seasons with the New Orleans Saints.
 After eight seasons on the coaching staff of the Rutgers Scarlet Knights football team, Hewitt was the special teams coach for the Baltimore Ravens and was the assistant secondary coach for the 2014 season.
Baltimore Ravens Cheerleaders
The Baltimore Ravens Cheerleaders are a cheerleading and dance squad for the Baltimore Ravens of the National Football League.
 Unlike other NFL Cheerleading squads, the Ravens squad is a co-ed squad, with the female cheerleaders doing various dance moves, and the males working on stunts, as in traditional cheerleading.
 The group was founded in 1998, and currently consists of 48 members (20 stunt team performers and 28 dancers).
 The squad performs at the Ravens home stadium M&T Bank Stadium.
 The squad's director is Tina Galdieri, who cheered at the 1996 Summer Olympics in Atlanta, as well as the WLAF's (later NFL Europe) Barcelona Dragons, and also led the University of Maryland's cheerleading squad to a National Championship in 1999.
 The squad also has a "Lil Ravens" summer program, and unlike the other squads, boys also are permitted to join.
 The group makes various appearances at parties and corporate functions throughout the year.
 The female members of the squad also has a swimsuit calendar, with their 2012 calendar taking place in the Bahamas.
 The squad currently has 31 female members.
2015 Baltimore Ravens season
The Baltimore Ravens season was the franchise's 20th season in the National Football League (NFL) and the eighth under head coach John Harbaugh.
 Although picked by some, including "Sports Illustrated"'s Peter King, to reach the Super Bowl, they had a disappointing season in part due to injuries.
 14 of their games were decided by 8 points or less and Joe Flacco, Justin Forsett, Steve Smith, Sr., and Terrell Suggs all suffered season ending injuries.
 They were eliminated from playoff contention in Week 14 with a loss to the Seattle Seahawks, in which they also suffered their ninth loss, resulting their first losing season in the Harbaugh–Flacco era and first since the collapse of the Brian Billick era.
 Ultimately the Ravens finished with a 5–11 record and twenty-two players ended the season on Injured Reserve.
2000 Baltimore Ravens season
The Baltimore Ravens season was the franchise's 5th season in the National Football League (NFL) and the second under head coach Brian Billick.
Vashone Adams
Vashone LaRay Adams (born September 12, 1973) is a retired American professional football player who played five seasons in the National Football League with the Cleveland Browns, Baltimore Ravens New Orleans Saints, Kansas City Chiefs and Dallas Cowboys.
 Adams first attended Fort Hays State University and Butte Junior College before transferring to Eastern Michigan University.
 After college, Adams was signed as an undrafted free agent by the Cleveland Browns.
 In his rookie season of 1995, Adams played in 8 games, started 6 of them and recorded 23 tackles.
 The following season, the Cleveland Browns moved to Baltimore and became the Baltimore Ravens.
 While with the Ravens, Adams recorded the only interception of his career, returning it for 15 yards.
 Adams joined the New Orleans Saints for the final season of his career, playing in 5 games, earning 4 starts and recording his only forced fumble.
 He would later sign contracts with the Kansas City Chiefs in 1998 and Dallas Cowboys in 1999.

Answer: 6th season