Question: What artist featured in the "Albert Einstein" album was one half of the hip-hop duo Mobb Deep?
Context: "Back at You" is a 1996 single by hip-hop duo Mobb Deep.  The song was featured on the soundtrack album for the film "Sunset Park".  The b-side featured another song from the film's soundtrack, "Elements I'm Among" by Queen Latifah. Black Cocaine is an extended play by hip hop duo Mobb Deep.  It's the first project by the duo since Prodigy's release from prison, posing the prospects of another group album after a long hiatus.  The project was announced by producer The Alchemist through his Twitter account.  The songs "Conquer", "Get It Forever" and "Waterboarding" were later featured as bonus tracks on their 2014 album "The Infamous Mobb Deep". Kejuan Muchita (born May 21, 1974), better known by his stage name Havoc, is an American rapper and record producer.  He was one half of the hip-hop duo Mobb Deep. Life of the Infamous: The Best of Mobb Deep is the greatest hits album from Queensbridge rap duo Mobb Deep.  It contains songs dating back to their 1993 debut album, "Juvenile Hell", through their 2004 album, "Amerikaz Nightmare".  No "Blood Money" songs are on the album since those tracks are owned by Universal Music Group, not Sony Music Entertainment, the label that released this album.  The disc includes "Blood Money" and "Go Head", two previously unreleased tracks.  "Keep It Thoro" is the only song featured on a non-Mobb Deep album (Prodigy's "H.N.I.C."). Albert Einstein is the second collaborative studio album by American hip hop recording artist Prodigy of Mobb Deep and American record producer The Alchemist.  The album was released on June 11, 2013, by Infamous Records.  The album features guest appearances from Roc Marciano, Domo Genesis, The Alchemist, Havoc, Raekwon and Action Bronson. The Infamous (stylized as The Infamous...) is the second studio album by the American hip hop duo Mobb Deep.  It was released on April 25, 1995, by Loud Records.  The album features guest appearances by Nas, Raekwon, Ghostface Killah, and Q-Tip, who also contributed to the production and mixing of the album.  Embedded with hyper-visual lyricism, dark soundscapes, gritty narratives, and hard beats, it marked Mobb Deep's transition from a relatively unknown rap duo to an influential and commercially successful one.  Most of the left-over songs from the album became bonus tracks for Mobb Deep's "The Infamous Mobb Deep" album (2014). Amerikaz Nightmare is the sixth studio album by hip-hop duo Mobb Deep.  The album was released on Jive Records, through a deal with the group’s own imprint.  It features the singles "Got It Twisted" and "Real Gangstaz."  The album debuted at #4 on the "Billboard" 200 with approximately 109,000 copies sold in its first week of release.  The album sold around 400,000 copies.  The album is seen as one of the duo's weaker releases, and the poor album sales are because of the lack of promotion and distribution the group received from its record label. The Infamous Archives is an album by Queensbridge hip-hop duo Mobb Deep on March 13, 2007.  The album consists of previously unreleased tracks.  The first disc contains Mobb Deep's "Back from a Hiatus" mixtape from 1998.  Rappers such as Sticky Fingaz, 50 Cent, Snoop Dogg and Busta Rhymes are featured.  The song "In the Long Run", Prodigy spoke about the altercation between him and Keith Murray.  In Prodigy's book, he stated this release wasn't authorized by the group. The discography of Prodigy, an American hip hop recording artist & One-half of the hip-hop duo Mobb Deep, consists of 5 studio albums, 3 collaborative albums, 1 EP, 5 mixtapes and 17 singles. The Infamous Mobb Deep is the eighth and final studio album by American hip hop duo Mobb Deep, which is composed of Havoc and Prodigy.  The album was released on April 1, 2014, by Prodigy's Infamous Records and Sony's RED Distribution.  "The Infamous Mobb Deep" is a double album that consists of one disc of new original music and another of unreleased tracks from the recording sessions from their second studio album "The Infamous" (1995).  The album has been in development since 2011, but was delayed by a feud that occurred between Havoc and Prodigy during 2012.  However, they shortly reconciled.
Answer: Havoc