Ravi is a South Korean rapper, songwriter and producer, signed under Jellyfish Entertainment.
 He began his career as a rapper in 2012 in the South Korean boy group VIXX, and later formed VIXX's first sub-unit VIXX LR with band mate Leo in 2015.
 Ravi's songwriting career began with his participation in co-writing VIXX's debut single "Super Hero".
 As of November 2016 with the release of "VIXX 2016 Conception Ker", Ravi has contributed to the writing and composing of over 46 songs recorded by VIXX.
 Ravi is widely known for his participation of composing and songwriting rap portions for the group as well as lyrics and music.
South Korean rapper and singer Bobby debuted as a member of the South Korean hip hop group iKON.
 His discography as a solo artist began in 2014.
 His self-produced debut album "Love and Fall" was released in 2017.
 As a member of the duo MOBB with Mino, he has released one collaboration album as well as several other singles and featured singles.
Song Min-ho (Hangul: 송민호 ; born March 30, 1993), better known by the stage name Mino, is a South Korean rapper, song writer, producer and member of the boy group Winner, signed under YG Entertainment.
Choi Jun-hong (Hangul: 최준홍; born October 15, 1996) better known by his stage name Zelo, is a South Korean rapper, dancer, singer and beatboxer.
 He is best known as a member of the South Korean boy group B.A.P.
 He made his recording debut with the single "Never Give Up" under B.A.P's sub-unit Bang&Zelo in November 2011.
 He is currently signed under TS Entertainment.
MOBB (stands for Mino and Bobby) is a South Korean hip hop sub-unit formed by YG Entertainment in 2016.
 The act consists of Mino (also in the group Winner) and Bobby (also in the group iKON).
The Gwiyomi Song, or Kwiyomi Song (귀요미 송), is a K-pop single by South Korean singer Hari and was released on February 18, 2013.
 It was inspired by a gesture from South Korean rapper Jung Ilhoon of boy group BtoB.
 The gesture is called 'Gwiyomi Player', that was popularized by South Korean variety show "Weekly Idol" through a segment called "The Aegyo Battle" (Battle of Cuteness) following Ilhoon's guest appearance on the show in October 2012.
 The song went on to be a viral success and an Internet meme after Korean Media outlet "Sports Seoul" uploaded a clip of Hari performing the gestures and singing the song.
 This video has since inspired many Asian netizens to upload their own versions onto the internet.
The Mobb (stylized as The MOBB) is debut album by South Korea hip-hop duo MOBB.
 The album was released online on September 8, 2016 and physically on September 23, 2016, by YG Entertainment.
 The album consist of 2 songs from the duo called "Hit Me" and "Full House", Mino's solo song "Body" and Bobby's solo song "HOLUP!"
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 The physical edition add 2 bonus songs which is "Fear" (MINO solo) and "가드올리고 Bounce" (Bobby solo).
Kim Won-sik (Hangul: 김원식 , born February 15, 1993) better known by his stage name Ravi (Hangul: 라비 ), is a South Korean rapper, singer-songwriter, producer, signed under Jellyfish Entertainment.
 He is a member of the South Korean boy group VIXX and VIXX sub-unit VIXX LR.
 He debuted as a solo artist on January 9, 2017, with the release of his debut mini album "R.EAL1ZE".
Lee Seung-hoon (born January 11, 1992), better known by the mononym Seunghoon, is a South Korean singer, rapper, songwriter and choreographer.
 He is a member of the South Korean boy group Winner.
 Prior to his debut, he appeared in the first season of the television singing contest "K-pop Star", finishing in fourth place.
Kim Jin-woo (born September 26, 1991), better known mononymously Jinwoo or Jinu, is a South Korean singer and actor.
 He is the lead vocalist of the South Korean boy group Winner, formed in 2013 by YG Entertainment through the survival show "WIN: Who Is Next".

Question: South Korean rapper and singer Bobby is a a member of the duo MOBB with a member of the boy group Winner, signed under who?
Answer: YG Entertainment