Question: Geoff Knorr worked on several video game titles, including what turn-based 4X video game that was developed by Firaxis Games?
Context: Geoff Knorr (born 13 June 1985) is an American composer, orchestrator, and sound designer.  He has worked on video game titles such as "Civilization V", "", "Civilization VI", "Galactic Civilizations III", and "Ashes of the Singularity". Dr. Jeffery L. Briggs (born March 10, 1957, in Florence, Alabama) is founder and former President and CEO of Firaxis Games, a video game developer based in Hunt Valley, Maryland, United States.  He was previously a game designer at MicroProse but left that company in 1996 along with Sid Meier and Brian Reynolds to form Firaxis Games. Sid Meier's Civilization Revolution is a 4X turn-based strategy video game, developed in 2008 by Firaxis Games with Sid Meier as designer.  It is a spin-off of the "Civilization" series.  The game was released for the PlayStation 3, Xbox 360, Nintendo DS, Windows Phone, and iOS.  A Wii version was originally expected but was put on indefinite hold.  The lack of a PlayStation Portable version was attributed to a lack of development manpower. Gamebryo is a game engine.  Gamebryo 3D and LightSpeed engines are owned by Gamebase Co., Ltd. and Gamebase USA and have been used by several video game developers including Atlus, Trion Worlds, 2K Games, Disney, Ubisoft, Bethesda Softworks, Firaxis Games, Tencent, Sony, Shanda, NCsoft, Rockstar Games and KingsIsle Entertainment for numerous cross-platform game titles. XCOM 2 is a turn-based tactics video game developed by Firaxis Games and published by 2K Games.  It was released for Microsoft Windows, OS X, and Linux in February 2016, and for PlayStation 4 and Xbox One in September 2016.  "XCOM 2" is the sequel to 2012's reboot of the series, "".  Taking place 20 years after the events of "Enemy Unknown", it follows the continuity that XCOM, a military organization trying to fight off an alien invasion, has lost the war, and is now a resistance force against their occupation of Earth. Sid Meier's Starships is a turn-based strategy video game developed by Firaxis Games and published by 2K Games.  It was released on March 12, 2015 for Microsoft Windows, OS X, and iOS.  The game is a stand-alone title but shares the same universe as "", putting the player in control of a fleet of space-faring craft.  The player will use the fleet to explore the galaxy, meeting other human and alien forces, and dealing with problems through a combination of military, diplomatic, and other strategic options.  Spacecraft in the fleet can be highly customized for meeting certain goals.  The game features cross-connectivity features with "Beyond Earth" for those that own both titles. Sid Meier's Civilization V is a 4X video game in the "Civilization" series developed by Firaxis Games.  The game was released on Microsoft Windows in September 2010, on OS X on November 23, 2010, and on Linux on June 10, 2014. Sid Meier's Civilization: Beyond Earth is a turn-based strategy, 4X video game in the "Civilization" series developed by Firaxis Games, published by 2K Games and released for Microsoft Windows on October 24, 2014, the Mac App Store on November 27, 2014 and for Linux on December 18, 2014.  A spiritual successor to "Alpha Centauri", "Beyond Earth" shares much of that game's development team, as well as some concepts which were introduced in the 1999 title.  The game's setting is unique to the "Civilization" series in that it takes place in the future, with mankind traveling through space and founding colonies on extraterrestrial planets after Earth becomes uninhabitable due to an undescribed disaster known as "the Great Mistake". Sid Meier's Civilization Revolution 2 is a 4X turn-based strategy video game for portable platforms, developed in 2014 by Firaxis Games with Sid Meier as designer.  It is a spin-off of the "Civilization" series and a sequel to "Civilization Revolution". Sid Meier's Civilization VI is a turn-based 4X video game and the sixth main title in the "Civilization" series.  "Civilization VI" was developed by Firaxis Games, published by 2K Games, and distributed by Take-Two Interactive.  The game was released on October 21, 2016 for Microsoft Windows and on October 24, 2016 for OS X.  A port for Linux was released on February 9, 2017.
Answer: Civilization VI