Question: Who was the producer of the studio album that was supported by Pearl Jam's Vs. Tour?

Context paragraphs:
Rearviewmirror: "Rearviewmirror" is a song by the American rock band Pearl Jam.  The song is the eighth track on the band's second studio album, "Vs." (1993).  Although credited to all members of Pearl Jam, it was primarily written by vocalist Eddie Vedder.  The song was included on Pearl Jam's 2004 greatest hits album, "rearviewmirror (Greatest Hits 1991–2003)".

Pearl Jam (album): Pearl Jam (sometimes referred to as The Avocado Album or simply Avocado) is the eighth studio album by American alternative rock band Pearl Jam, released on May 2, 2006 on J Records.  It was the first and only release for J Records, their last album issued by Sony Music.  It was the band's first full-length studio release in almost four years, since "Riot Act" (2002).  Following their performances at the Vote For Change tour in 2004, the band commenced work on "Pearl Jam" in November 2004 at Studio X in Seattle, Washington and finished in February 2006.

Vitalogy: Vitalogy is the third studio album by the American rock band Pearl Jam, released on November 22, 1994, through Epic Records.  Pearl Jam wrote and recorded "Vitalogy" while touring behind its previous album "Vs." (1993).  The music on the record was more diverse than previous releases, and consists of aggressive rock songs, ballads and other elements making this Pearl Jam's first experimental album.

Vs. (Pearl Jam album): Vs. is the second studio album by American rock band Pearl Jam, released on October 19, 1993 through Epic Records.  After a relentless touring schedule in support of their 1991 debut album "Ten", Pearl Jam headed into the studio in early 1993 facing the challenge of following up the commercial success of its debut.  The resulting album, "Vs.", featured a rawer and more aggressive sound compared with the band's previous release.  It was the band's first collaboration with producer Brendan O'Brien, and their first album with drummer Dave Abbruzzese.

Animal (Pearl Jam song): "Animal" is a song by the American rock band Pearl Jam, released in 1994 as the third single from the band's second studio album, "Vs." (1993).  Although credited to all members of Pearl Jam, it features lyrics written by vocalist Eddie Vedder and music primarily written by guitarist Stone Gossard.  The song peaked at number 21 on the "Billboard" Mainstream Rock Tracks chart.  The song was included on Pearl Jam's 2004 greatest hits album, "rearviewmirror (Greatest Hits 1991–2003)".

Elderly Woman Behind the Counter in a Small Town: "Elderly Woman Behind the Counter in a Small Town" is a song by the American rock band Pearl Jam.  The song is the tenth track on the band's second studio album, "Vs." (1993).  Although credited to all members of Pearl Jam, it was primarily written by vocalist Eddie Vedder.  The length of the song's title was a reaction by the band to the fact that most of its songs featured one-word titles.  The song is often referred to simply as "Small Town" by the band and its fans.  Despite the lack of a commercial single release, the song managed to reach number 17 on the "Billboard" Modern Rock Tracks chart.  An acoustic version of the song can be found on the "Go" single.  The song was included on Pearl Jam's 2004 greatest hits album, "rearviewmirror (Greatest Hits 1991–2003)".  The song was used in promos for the final season of "Rescue Me".

Vs. Tour: The Vs. Tour was a concert tour by the American rock band Pearl Jam to support its second album, "Vs."

Riot Act (album): Riot Act is the seventh studio album by American rock band Pearl Jam, released on November 12, 2002 through Epic Records.  Following a full-scale tour in support of its previous album, "Binaural" (2000), Pearl Jam took a year-long break.  The band then reconvened in the beginning of 2002 and commenced work on a new album.  The music on the record featured a diverse sound, including songs influenced by folk, art rock, and experimental rock.  The lyrics deal with mortality and existentialism, with much influence from both the political climate after the September 11, 2001 terrorist attacks and the accidental death of nine fans during Pearl Jam's performance at the 2000 Roskilde Festival.

Go (Pearl Jam song): "Go" is a song by the American rock band Pearl Jam, released in 1993 as the first single from the band's second studio album, "Vs." (1993).  Although credited to all members of Pearl Jam, it features lyrics written by vocalist Eddie Vedder and music primarily written by drummer Dave Abbruzzese.  The song peaked at number three on the "Billboard" Mainstream Rock Tracks chart.  The song was included on Pearl Jam's 2004 greatest hits album, "rearviewmirror (Greatest Hits 1991–2003)".

Daughter (song): "Daughter" is a song by the American rock band Pearl Jam, released in 1993 as the second single from the band's second studio album, "Vs." (1993).  Although credited to all members of Pearl Jam, it features lyrics written by vocalist Eddie Vedder and music primarily written by guitarist Stone Gossard.  The song topped both the Mainstream Rock and Modern Rock "Billboard" charts.  The song spent a total of eight weeks at number one on the Mainstream Rock chart.  "Daughter" eventually peaked at number 28 on the Top 40 Mainstream chart, becoming the band's first Top 40 single.  The song was included on Pearl Jam's 2004 greatest hits album, "rearviewmirror (Greatest Hits 1991–2003)".

Supporting paragraphs: Vs. Tour Vs. (Pearl Jam album)
Answer: Brendan O'Brien