Question: New Zealand top 50 singles of 2014 contained a song by Eminem that had guest vocals from what Barbadian singer?

Context paragraphs:
New Zealand top 50 albums of 2014: This is a list of the top-selling albums in New Zealand for 2014 from the Official New Zealand Music Chart's end-of-year chart, compiled by Recorded Music NZ.  The chart includes six albums by New Zealand artists, including two albums by brother-sister duo Broods.  The chart also includes 13 albums that featured in the New Zealand top 50 albums of 2013.  The 2014 chart was the first to include online streaming as well as sales data.

Grass (Animal Collective song): "Grass" is the first single from Animal Collective's 2005 album, "Feels".  Pitchfork Media listed the song at #31 on its list of Top 50 Singles of 2005, claiming it is "as infectious as anything on the pop charts this year, and lots more fun to scream along with".  The song was subsequently placed at #73 in the same publication's list of "Top 500 Tracks of the 2000s".  Stylus also placed it in its Top 50 Singles of 2005 (this time at #44), praising the band's ability to "play tug of war between typical pop dynamics and the skewed perspective of experimental music".  The title track was included in the 2008 book "The Pitchfork 500".

Pop Mechanix: Pop Mechanix was a New Zealand pop music band that played in New Zealand and Australia from 1979 to 1988.  Their hit single, "Jumping out a Window", reached number 87 of the all-time top 100 singles for APRA NZ, and number 12 in the all-time top 50 singles for The Press

Official New Zealand Music Chart: The Official New Zealand Music Chart is the weekly New Zealand top 40 singles and albums charts, issued weekly by Recorded Music NZ (formerly Recording Industry Association of New Zealand (RIANZ)).  The chart also includes the top-20 New Zealand artist singles and albums and top 10 compilation albums.  All charts are compiled from data of both physical and digital sales from music retailers in New Zealand.

New Zealand top 50 singles of 2014: This is a list of the top-selling singles in New Zealand for 2014 from the Official New Zealand Music Chart's end-of-year chart, compiled by Recorded Music NZ.  English singer-songwriter Ed Sheeran had the most songs in the top 50, with four.  The chart also includes three songs by New Zealand artists: "Freaks" by Australian DJ Timmy Trumpet and New Zealand rapper Savage, and "Holding You" by Ginny Blackmore and Stan Walker, and "Bridges" by Broods.  Four songs also featured in the New Zealand top 50 singles of 2013: Katy Perry's songs "Roar" and "Dark Horse", "I See Fire" by Ed Sheeran, "The Monster" by Eminem and "Timber" by Pitbull.  The 2014 chart was the first to include online streaming as well as sales data.

New Zealand top 50 albums of 2015: This is a list of the top-selling albums in New Zealand for 2015 from the Official New Zealand Music Chart's end-of-year chart, compiled by Recorded Music NZ.  The chart includes 12 albums by New Zealand artists, including two albums by popera trio Sole Mio.  The chart also includes 12 albums that featured in the New Zealand top 50 albums of 2014.

New Zealand Top 50 singles of 2008: This is a list of the Top 50 singles in 2008 in New Zealand, as listed by the Recording Industry Association of New Zealand (RIANZ).

Bass Player (album): Bass Player is the debut album by New Zealand reggae band, Rhombus.  It was released in 2003.  The album peaked at #18 in the New Zealand Top 40 Albums charts.  The song "Clav Dub" reached #16 in the New Zealand Top 40 Singles charts.

The Monster (song): "The Monster" is a song by American rapper Eminem, featuring guest vocals from Barbadian singer Rihanna, taken from Eminem's album "The Marshall Mathers LP 2" (2013).  The song was written by Eminem, Jon Bellion, and Bebe Rexha, with production handled by Frequency.  "The Monster" marks the fourth collaboration between Eminem and Rihanna, following "Love the Way You Lie", its sequel "Love the Way You Lie (Part II)" (2010), and "Numb" (2012).  "The Monster" was released on October 29, 2013, as the fourth single from the album.  The song's lyrics present Rihanna coming to grips with her inner demons, while Eminem ponders the negative effects of his fame.

Silencer (Zed album): Silencer is the debut studio album by New Zealand rock band Zed.  It was produced and engineered by David Nicholas at Revolver Studios in Auckland, New Zealand, with final overdubbing and mixing at Mangrove Studios, north of Sydney, Australia.  Recording sessions were over in seven weeks, but not before all band members and production staff were struck by influenza.  The album was first released in New Zealand on 27 August 2000, via Universal Music Group.  The album debuted at number one on the Official New Zealand Top 40 Albums chart, quickly achieving triple platinum status, and creating six hit singles.  "Renegade Fighter" was also the number one song in New Zealand for the year 2000.  In 2001, "Silencer" earned the band three wins at the New Zealand Music Awards including 'Album of the Year', 'Top Group', and 'Top Male Vocalist'.  A bonus disc edition was released in early 2001, containing ten bonus tracks and three music videos, "Renegade Fighter", "Come On Down" and "Driver's Side".

Supporting paragraphs: New Zealand top 50 singles of 2014 The Monster (song)
Answer: Rihanna