Question: What was the vocal range of the singer who recorded the song The Golden Boy with Montserrat Caballé ?

Context articles: The Golden Boy
Barcelona (album)
Amelia Sierra
Paulo Kafeero
Montserrat Caballé
Georgia Brown (Brazilian singer)
Barcelona (Freddie Mercury and Montserrat Caballé song)
Freddie Mercury
Friends for Life (Montserrat Caballé album)
Golden Boy (Kylie Minogue song)

"The Golden Boy" is a song recorded by Queen frontman Freddie Mercury together with Catalan operatic soprano Montserrat Caballé.
Barcelona is the second solo album recorded by Freddie Mercury, frontman of popular British rock band Queen, and operatic soprano Montserrat Caballé.
 Released in 1988.
 It is the second and final solo album recorded by Mercury.
Amelia Sierra is a soprano and mezzo-soprano opera singer from Mexico.
 Sierra was born in Mexico City and completed her musical studies with the Escuela Superior de Música of the INBA.
 She has studied under Maritza Alemán, James Demster, Mario Alberto Hernández and Ricardo Sánchez as well as Magda Olivero, Montserrat Caballé, Ramón Vargas, Francisco Araiza, Carmo Barbosa, Dalton Baldwin, Dolores Aldea, Lara Pasquinelli, Joan Dornemann, Tito Capobianco and Susan Young .
 While in training, she received recognition with Best Performance at the FONCA-OCJM in 1995, third place in the Carlo Morelli National Singing Contest and first place the OSUG Competition, both in 1996.
 She also received recognition by the National Coordination of Music and Opera in 1996.
 She has received various grants for performing from the Education for Art Program at the University of Guanajuato and SIVAM.
 She continues to study informally in various workshops in New York City.
Kafeero, Paul Job (1970–2007) (Prince Paul Job Kafeero, Paulo Kafeero, the Golden Boy of Africa), the most celebrated composer and singer in the Ugandan tradition of Kadongo Kamu.
 At the time of his death, he was planning to celebrate 20 years of an illustrious music career.
 His catalogue consists of 83 songs on 21 albums.
 It was his 1994 hit Walumbe Zaaya, a fifteen-minute lament on death in which no word is repeated, which sent him into the Ugandan musical stratosphere.
 That song earned him the enduring nickname the Golden Boy of Africa from the 1994 Cairo music festival attended by thousands of African contestants, where he won a gold medal from the Institute d'Etudes Theatreales.
 In 2003, his hit song Dipo Naziggala, which pokes fun at the drinking habits of Ugandans, won a Pearl of Africa Music Award (PAM) for best Kadongo Kamu single.
 In both 2003 and 2004, he won the PAM award for best Kadongo Kamu artist/group).
Montserrat Caballé (] ; born 12 April 1933) is a Spanish operatic soprano.
 She has sung a wide variety of roles, but Caballé is best known as an exponent of the works of Verdi and of the bel canto repertoire, notably the works of Rossini, Bellini, and Donizetti.
 She came to the attention of a much wider audience when she recorded at the request of the IOC in 1987 "Barcelona", a duet with Freddie Mercury, the lead singer of the British rock band Queen; the song was inspired by Caballé´s home city, later it was used as one of the two official theme songs for the 1992 Olympic Games.
Georgia Brown, pseudonym of Rossana Monti (born June 29, 1980) is an Italian Brazilian singer noted for her extensive vocal range.
 She was listed in the 2005 "Guinness World Records" for hitting the highest vocal note and for possessing the greatest vocal range for a female, claimed to be exactly eight octaves from G-G using scientific pitch notation.
 However, as of 2013, Tim Storms holds the record for the widest vocal range of any human with 10 octaves.
Barcelona (Freddie Mercury and Montserrat Caballé song)
Farrokh "Freddie" Mercury (born Bulsara; 5 September 1946 – 24 November 1991) was a British singer, songwriter and record producer, known as the lead vocalist of the rock band Queen.
 He was known for his flamboyant stage persona and four-octave vocal range.
 Mercury wrote numerous hits for Queen, including "Bohemian Rhapsody", "Killer Queen", "Somebody to Love", "Don't Stop Me Now", "Crazy Little Thing Called Love", and "We Are the Champions".
 He led a solo career while performing with Queen, and occasionally served as a producer and guest musician for other artists.
Friends for Life is a 1997 album by Spanish opera singer Montserrat Caballé.
"Golden Boy" is a song by Australian singer Kylie Minogue, released on 19 April 2014 for Record Store Day.
 The song was released exclusively on 7" vinyl by Parlophone, and later for digital download by British retailer HMV.
 1000 records were pressed for the song.
 "Golden Boy" was originally intended to be included on the Japanese edition of Minogue's twelfth studio album "Kiss Me Once", but was eventually left unused.
 The song was written by Ariel Rechtshaid, Dan Nigro and Justin Raisen, and produced by Rechtshaid.