Question: What was the nationality of the WBA titleholder that Derrick Gainer lost to in a unanimous decision since his defeat to Juan Manuel Márquez?

full_context: Document 1: Justin Juuko: Justin "The Destroyer" Juuko (born 26 December 1972 in Masaka) is a Ugandan amateur light flyweight and professional feather/super feather/light/light welter/welterweight boxer of the 1990s, 2000s and 2010s who as an amateur won the gold medal at light flyweight in the Boxing at the 1990 Commonwealth Games in Auckland, New Zealand, and as a professional won the World Boxing Council (WBC) International super featherweight title, World Boxing Council (WBC) FECARBOX super featherweight title, African Boxing Union (ABU) light welterweight title, North American Boxing Federation (NABF) super featherweight title, and Commonwealth super featherweight title, and was a challenger for the interim World Boxing Association (WBA) World super featherweight title against Antonio Hernandez, World Boxing Council (WBC) super featherweight title against Floyd Mayweather, Jr., International Boxing Association (IBA) super featherweight title against Diego Corrales, World Boxing Union (WBU) super featherweight title against Michael Gomez, International Boxing Association (IBA) lightweight title against Rustam Nugaev, Global Boxing Union (GBU) light welterweight title against Gábor Vető, his professional fighting weight varied from 125 lb , i.e. featherweight to 143 lb , i.e. welterweight.
Document 2: Juan Manuel Márquez vs. Joel Casamayor: Juan Manuel Márquez vs. Joel Casamayor was a boxing lightweight superfight. In 2008 reigning lightweight Champion "El Cepillo" Casamayor met former two-division World Champion Juan Manuel "Dinamita" Márquez at the MGM Grand Garden Arena in Las Vegas for a 12-round championship bout. Casamayor was the champion of boxing's lightweight division, recognized as the title holder by Ring Magazine, even though he didn't own any of the belts from boxing's four major sanctioning bodies.
Document 3: Gerry Peñalosa: Geronimo "Gerry" Peñalosa (born August 7, 1972) is a Filipino former professional boxer who competed from 1989 to 2010. He is a two-weight world champion, having held the WBC and lineal super flyweight titles from 1997 to 1998, and the WBO bantamweight title from 2007 to 2009. Originally from San Carlos City, Peñalosa currently resides in Manila. He was trained mainly by Freddie Roach, and went on to become a boxing trainer himself after retirement. Peñalosa's older brother, Dodie Boy Peñalosa, is also a former boxer and world champion.
Document 4: Juan Manuel Márquez vs. Juan Díaz: Juan Manuel Márquez vs. Juan Diaz was a boxing lightweight title superfight, for the vacant WBO/WBA lightweight championship, and Marquez's "The Ring" lightweight title. The bout was held on February 28, 2009, at the Toyota Center in Houston, Texas, United States. Marquez won the fight via technical knockout in the ninth round.
Document 5: Chris Dolman: Christiaan "Chris" Dolman (born February 17, 1945) is a Dutch retired martial artist and professional wrestler. He won a silver medal at the European championship in judo and a gold at the world championship in Sambo, counting as the first non-Russian sambo world champion, and has over 40 national and 10 international championships. He is known for his career in Fighting Network Rings and for his role training several Dutch mixed martial artists and kickboxers, among them Bas Rutten, Alistair and Valentijn Overeem, Gilbert Yvel and Gegard Mousasi.
Document 6: Chris John (boxer): Yohannes Christian "Chris" John (born September 14, 1979) is an Indonesian former professional boxer and world champion, who competed from 1998 to 2013.
Document 7: Roy Jones Jr.: Roy Levesta Jones Jr. (born January 16, 1969) is an American professional boxer, boxing commentator, boxing trainer, rapper, and actor who holds dual American and Russian citizenship. He is a six-time former world champion in four weight classes, having held titles at middleweight, super middleweight, light heavyweight, and heavyweight; and is the only boxer in history to start his professional career at light middleweight and go on to win a heavyweight title. As an amateur he represented the United States at the 1988 Summer Olympics, winning a silver medal in the light middleweight division.
Document 8: Derrick Gainer: Derrick "Smoke" Gainer (born August 22, 1972, in Pensacola, Florida) is a US born boxer who started out in the featherweight division and now fights in the lightweight division. In 2000, he defeated Freddie Norwood to win the World Boxing Association (WBA) featherweight title and after four defenses lost to Juan Manuel Márquez, who became super champion, via technical decision in 2003. Since his defeat to Marquez, Gainer lost in a challenge to WBA titleholder Chris John via unanimous decision. Gainer is also a colleague and good friend of Roy Jones Jr., and often fought on his under-cards.
Document 9: Joe Calzaghe: Joseph William Calzaghe, {'1': ", '2': ", '3': ", '4': "} ( ; born 23 March 1972) is a Welsh former professional boxer who competed from 1993 to 2008. He is a two-weight world champion, having held the unified WBA (Super), WBC, IBF, WBO, "Ring" magazine, and lineal super-middleweight titles, as well as the "Ring" light-heavyweight title. Calzaghe is the longest-reigning super-middleweight world champion in boxing history, having held the WBO title for over 10 years and making 21 successful defences before moving up to light-heavyweight. As his super-middleweight and light-heavyweight reigns overlapped, he retired with the longest continual time as world champion of any active fighter.
Document 10: Juan Manuel Márquez: Juan Manuel Márquez Méndez (born August 23, 1973) is a Mexican former professional boxer who competed from 1993 to 2014. He is the third Mexican boxer (after Érik Morales and Jorge Arce) to become a four-weight world champion, having formerly held nine world championships including the WBA (Super), IBF, and WBO featherweight titles between 2003 and 2007; the WBC super featherweight title from 2007 to 2008; the WBA (Super), WBO, "Ring" magazine, and lineal lightweight titles between 2008 and 2012; and the WBO junior welterweight title from 2012 to 2013.
Document 11: Chris Eubank: Christopher Livingstone Eubanks (born 8 August 1966), known as Chris Eubank, is a British former professional boxer who competed from 1985 to 1998. He held the WBO middleweight and super-middleweight titles, scoring victories over six world champions, and is ranked by BoxRec as the third best British super-middleweight boxer of all time.
Document 12: Chris Eubank Jr.: Christopher Livingstone "Chris" Eubank Jr. (born 18 September 1989) is a British professional boxer. He has held the IBO super-middleweight title since February 2017, having previously held the WBA interim and British middleweight titles between 2015 and 2016. As of July 2017, Eubank Jr. is ranked as the world's second best super middleweight by BoxRec, sixth by the Transnational Boxing Rankings Board, and seventh by "The Ring" magazine. He is the son of former two-weight world boxing champion Chris Eubank.
Document 13: Freddie Norwood: Freddie Norwood (born February 14, 1970 in St. Louis, Missouri) is a boxer in the lightweight division. Known as "Lil Hagler", Norwood defeated Antonio Cermeño to win the WBA Featherweight Title in 1998. He successfully defended his title eight times before losing his title by a controversial 11th-round TKO to Smoke Gainer. Among his notable defenses were a 9th-round KO over former WBC Featherweight Title holder Takashi Koshimoto, a unanimous decision victory over former WBO Featherweight Title holder Julio Pablo Chacón and former IBF and WBA Featherweight title holder Juan Manuel Márquez. After losing his title to Gainer, Norwood retired from boxing.
Document 14: Juan Manuel Márquez vs. Juan Díaz II: Juan Manuel Márquez vs. Juan Diaz was a boxing lightweight title superfight, in a rematch of the 2009 Fight of the Year. Marquez, went to Diaz's hometown of Houston to face him at the Toyota Center in February 2009 in what turned out to be an all-action slugfest, one that Marquez won via ninth-round knockout.
Document 15: Chris Bacon (boxer): Christopher P. "Chris" Bacon (born 8 October 1969) is a retired professional British cruiserweight boxer and judoka born in Tasmania, Australia and residing in Manchester. During his professional boxing career he was trained by Bob Shannon a long-time Manchester boxing coach. He is a former WBF European Super Cruiserweight Champion, former National Judo Champion, and Bronze medal winner at the 1990 Commonwealth Games. Bacon has professionally wrestled in Japan, is former MMA fighter and also participated in the 1992 Summer Olympics in Barcelona.
ground_truth: Indonesian