Question: Who sings the rap in Baby by the performer in My World Tour?

full_context: Document 1: When I Was Your Man: ``When I Was Your Man ''was written by Andrew Wyatt, Bruno Mars, Philip Lawrence and Ari Levine, while production was handled by the latter three production - team The Smeezingtons. Having chord progressions Am - C - Dm - G - G7 - C (verse) and F-G-C (chorus), the song is written in the key of C Major, with Mars' vocals range from the low note of G3 to the high note of C5. The pop piano ballad finds Mars singing about a pre-fame heartbreak as he regrets letting his woman get away. It starts with a rolling piano riff; unto a nearly scat`` vocal cadence'': ``Same bed but it feels just a little bit bigger now / Our song on the radio but it do n't sound the same '', as he laments the`` single state'' he created for himself. Next, he sings of his failings; to do right by his woman, ``I shoulda bought you flowers / And held your hand / Shoulda gave you all my hours / When I had the chance ''. Its title phrase re-emerges in the final chorus, juxtaposed by Bruno from all the things he`` shoulda'' done, into things he hopes his ex's new man will do; concluding: ``Do all of the things I should have done / When I was your man ''. In an interview to Rolling Stone, Mars revealed, while reluctant, that he wrote the song for his girlfriend, model Jessica Caban, when he was worried about losing her. In contrast with the song, Mars and Caban stayed together; remaining a couple as of 2014. Mars also said, in the interview, that he finds it difficult to perform the song; saying:`` You're bringing up all these old emotions again,'' and that: ``It's just like bleeding! ''
Document 2: Love Yourself: Lyrically, ``Love Yourself ''is a kiss - off to a narcissistic ex-lover who did the protagonist wrong, with Bieber singing in a snappy and spiteful tone while`` hating on a girl for loving herself too much.'' In the pre-chorus, he sings with a husky tone in the lower registers: ``My mama do n't like you, and she likes everyone, ''`` in a style that molds well to Sheeran's,'' according to Rolling Stone's Brittany Spanos. ``And I (never) like to admit that I was wrong. And I've been so caught up in my job, did n't see what's going on, and now I know, I'm better sleeping on my own, ''he continues. In the chorus, Bieber sings,`` Cause if you like the way you look that much, oh baby you should go and love yourself,'' which according to Digital Spy's Amy Davidson, ``'love yourself' means' go f * * k yourself 'in this context. ''On March 7, 2017, composer Ed Sheeran stated on the Howard Stern Show that he had Rihanna in mind for the song at first, and the original lyric was indeed`` fuck yourself.'' In the song's bridge, Bieber uses a ``brass - and - vocalese ''style.
Document 3: Believe Tour: The Believe Tour was the second concert tour by Canadian pop star Justin Bieber. It was launched in support of his third studio album, "Believe" (2012). Beginning in September 2012, the tour played over 150 shows in the Americas, Europe, Asia, Africa, and Australasia.
Document 4: Purpose World Tour: The Purpose World Tour is the third worldwide tour by Canadian singer Justin Bieber. It was in support of his fourth studio album Purpose (2015). The tour started on March 9, 2016 in Seattle and ended on July 2, 2017 in London, England.
Document 5: Baby (Justin Bieber song): Filming for the music video began during the week of January 25, 2010, in Los Angeles. It was filmed at Universal CityWalk by director Ray Kay, who had previously directed videos for Beyoncé Knowles, Lady Gaga, Alexandra Burke, and Cheryl Cole, among others. Ludacris said that the video ``is like a 2010 version of Michael Jackson's`` The Way You Make Me Feel ''.'' Bieber said that the video ``will capture the song's message of trying to woo back a girl. ''In explaining the concept of the video, Bieber said,`` It starts off, I really like this girl, but we did n't (get) along; we could n't be together. Basically I want her back and (I'm) kind of going through the whole thing. I'm chasing her around, trying to get her, and she's kind of playing hard to get, but I'm persistent. I keep going.'' The video premiered exclusively on Vevo on Friday, February 19, 2010. Singer and actress Jasmine Villegas portrays Bieber's love interest in the video. Bieber's friends, Young Money artists Drake and Lil Twist also appeared in the video, along with Tinashe and jerkin 'crew The Rangers.
Document 6: My World Tour: The My World Tour was the debut concert tour by Canadian recording artist Justin Bieber. It is Bieber's first concert tour which supports his two-part debut album "My World" and "My World 2.0". The tour was for the first time rocky teswin officially announced on March 16, 2010, a week before "My World 2.0" was released. The tour has multiple legs with the supporting acts of Mindless Behavior, Sean Kingston and Jessica Jarrell on North American dates and pop girl group The Stunners also joined the tour for the first twenty dates. Jasmine Villegas joined the tour as opening act for the second leg. The first leg of the tour is estimated to have grossed $35.6 million post inflation. The tour made a total of $53,341,886 worldwide.
Document 7: All Around the World (Justin Bieber song): "All Around the World" is a song by Canadian singer Justin Bieber, from his third studio album, "Believe" (2012). It was written by Bieber, Sir Nolan and Nasri of The Messengers in collaboration with Ludacris, who guest features. This was the second collaboration between Bieber and Ludacris, having previously collaborated on "Baby" (2010). It was first released on June 4, 2012, as a promotional single from the album. The song was released as the fourth international single, and the fifth and final US single on February 26, 2013. The Eurodance track features a similar instrumentation to songs by Britney Spears, Chris Brown and Usher. Lyrically, it features Bieber singing to his love interest that "all around the world, people want to be loved". "All Around the World" received mostly positive reviews from music critics, who welcomed the song's Eurodance style. The song had moderate success worldwide, reaching the top ten in several countries, such as Belgium, Canada and Norway. Bieber promoted the song through live performances and a music video.
Document 8: Somebody to Love (Justin Bieber song): "Somebody to Love" is a song performed by Canadian recording artist Justin Bieber. The song served as the second single from his album, "My World 2.0". It was written by Heather Bright and The Stereotypes, and produced by the latter. The song was originally recorded as a demo by Bieber's mentor, R&B singer, Usher, for his sixth studio album, "Raymond v. Raymond" (2010). After things went stale with Usher's label, The Stereotypes were encouraged to give the song to Bieber, who recorded it, with Usher performing background vocals. The song is an upbeat pop song, which also derives from R&B genre, while making use of Eurodisco influences. It impacted US mainstream and rhythmic radio on April 20, 2010. The remix of the song featuring Usher was featured on Bieber's first compilation album "" and his second remix album "".
Document 9: Fearless Tour: The Fearless Tour was the debut concert tour by American singer-songwriter Taylor Swift. Also referred to as the Fearless Tour 2009 and the Fearless Tour 2010, it was launched in support of her second studio album ""Fearless"" (2008). On the tour, she was joined by guests Kellie Pickler and Gloriana. Teen singer Justin Bieber joined her as an opening act for the tour when she went to England in November 2009. During the tour, Swift performed with guests such as John Mayer, Katy Perry, and Faith Hill. It grossed $63,705,590 from 89 reported shows and an audience of 1,138,977.
Document 10: Love Yourself: ``Love Yourself ''is a song recorded by Canadian singer Justin Bieber for his fourth studio album Purpose (2015). The song was released first as a promotional single on November 8, 2015, and later was released as the album's third single. It was written by Ed Sheeran, Benny Blanco and Bieber, and produced by Blanco. An acoustic pop song,`` Love Yourself'' features an electric guitar and a brief flurry of trumpets as its main instrumentation. During the song, Bieber uses a husky tone in the lower registers. Lyrically, the song is a kiss - off to a narcissistic ex-lover who did the protagonist wrong.
Document 11: Baby (Justin Bieber song): The song is predominantly upbeat, featuring Bieber's R&B vocals over a backdrop containing a dance infused beat, full of keyboard and ``disco string ''synths. The song is composed in the key of E ♭ major with Bieber's vocal range spanning from the low - note of G to the high - note of C. According to Jody Rosen of Rolling Stone, the song`` blends winks at Fifties doo - wop with hip - hop chants'', comparing the style and the lyrics ``My first love broke my heart for the first time / And I was like / Baby, baby, baby, ooooh / I thought you'd always be mine ''to fifties ballads like`` Tears on My Pillow'', ``Why Do Fools Fall in Love ''and`` Earth Angel''. Lyrically, Bieber's lines explain his distress over his lost love, and promise to get it back, featured in lines like, ``And I wan na play it cool / But I'm losin 'you... / I'm in pieces / So come and fix me... ''. The chorus features the distinct and repetitive`` baby, baby, baby, ohhhh (nooooo)'' hook. After the second verse, Ludacris comes in with the verse - rap, an anecdote of young love when he was thirteen, as it runs ``When I was 13 / I had my first love / She had me going crazy / Oh, I was star - struck / She woke me up daily / Do n't need no Starbucks... ''.
Document 12: Justin Bieber: Justin Drew Bieber (/ ˈbiːbər /; born March 1, 1994) is a Canadian singer and songwriter. After a talent manager discovered him through his YouTube videos covering songs in 2008 and signed to RBMG, Bieber released his debut EP, My World, in late 2009. It was certified Platinum in the U.S. He became the first artist to have seven songs from a debut record chart on the Billboard Hot 100. Bieber released his first full - length studio album, My World 2.0, in 2010. It debuted at or near number one in several countries, was certified triple Platinum in the U.S., and contained his single ``Baby ''.
Document 13: Baby Boy (Beyoncé song): "Baby Boy" is a song by American singer Beyoncé featuring Jamaican dancehall singer Sean Paul from Beyoncé's debut solo studio album "Dangerously in Love" (2003). Both artists co-wrote the song with Scott Storch, Robert Waller and Shawn "Jay-Z" Carter; the former also co-produced the song. Containing a lyrical interpolation of "No Fear" by hip hop group O.G.C, "Baby Boy" is an R&B and dancehall song with reggae and Arabic music influences; its lyrics detail a woman's fantasies.
Document 14: Justin Bieber: Justin Drew Bieber (/ ˈbiːbər /; born March 1, 1994) is a Canadian singer, actor and songwriter. After a talent manager discovered him through his YouTube videos covering songs in 2008 and he signed to RBMG, Bieber released his debut EP, My World, in late 2009. It was certified platinum in the U.S. He became the first artist to have seven songs from a debut record chart on the Billboard Hot 100. Bieber released his first full - length studio album, My World 2.0, in 2010. It debuted at or near number one in several countries, was certified triple platinum in the U.S., and contained his single ``Baby ''.
Document 15: Down to Earth (Justin Bieber song): "Down to Earth" is a song by Canadian recording artist Justin Bieber, included as a track on his debut release, "My World", released on November 17, 2009. It was written by Bieber, who was assisted by Carlos and Steven Battey of The Jackie Boyz, as well as the song's producers, Mason "MdL" Levy, and Kevin Risto and Waynne Nugent of Midi Mafia. "Down to Earth" is a teen pop song, with lyrics that were inspired by the divorce of Bieber's parents. It also contains lyrical content about growing up. The song received positive reviews from critics, who embraced the song as a shift in the puppy love content of the album. After the release of My World, due to digital sales, the song charted in the lower regions of charts in the United States, Canada, and the United Kingdom.
ground_truth: Ludacris
sub_queries: My World Tour >> participant Answer: Justin Bieber
who sings the rap in baby by Justin Bieber Answer: Ludacris