Question: What athlete did a Serbian traditional healer who has specialized in the use of horse placenta treatment to heal athletes used the horse placenta treatment on, she also treated  an Argentine professional footballer who plays as a right back for West Ham United and the Argentina national team?

Context paragraphs:
West Ham United F.C. Under-23s: West Ham United F.C. Under-23s, formerly West Ham United F.C. Under-21s is the most senior of West Ham United's youth teams.  The Under-23 team is effectively West Ham United's second-string side, but is limited to three outfield players and one goalkeeper over the age of 23 per game following the introduction of new regulations from the 2012–13 season.  They play in Premier League 2 and also compete in the Checkatrade Trophy.

Mark Noble: Mark James Noble (born 8 May 1987) is an English footballer who plays as a central midfielder and is captain of West Ham United.  He has played almost all his youth and first team football for West Ham apart from two short loan spells, at Hull City and Ipswich Town.  He has played for England at U16, U17, U18, U19 and U21 levels.  He captained the U21 side, scoring three goals in 20 appearances.  Noble is the longest serving player in West Ham's current squad, having been in the first team since 2004.  He is West Ham's first-choice taker for penalty kicks and has won the club's Hammer of the Year trophy twice.

Danny Williamson (footballer): Daniel 'Danny' Williamson (born 5 December 1973 in West Ham, London) is an English retired professional footballer who was a product of the West Ham United academy and played for West Ham United and Everton in the 1990s.  He played in midfield.

Reece Burke: Reece Frederick James Burke (born 2 September 1996) is an English professional footballer who plays as a defender for Bolton Wanderers, on loan from West Ham United.  He has also played for Bradford City where he was the player of the season for the 2015-16 season.  Internationally he has played for the England Under-18 team, England Under-19 team and England Under-20 team.  Burke mainly plays centre back, he can also play right back.

Mariana Kovacevic: Mariana Kovacevic is a Serbian traditional healer who has specialized in the use of horse placenta treatment to heal athletes.  During the duration of the 2012 African Cup of Nations in Gabon and Equatorial Guinea she used the horse placenta treatment to heal Ghana's Asamoah Gyan, who had been injured and was supposed to be off football for four weeks.  She is reported to have nursed him back to health in four hours.  She was also reportedly enlisted by the Serbia during the world of 2010 in south Africa.  Other footballers who are reported to have been treated by Mariana include Pablo Zabaleta, Vincent Kompany, Nigel de Jong and Robin Van Persie of Manchester United.  There has been some doubt as to whether Mariana's therapies work.  But more footballers are turning to her for help.

Pablo Zabaleta: Pablo Javier Zabaleta Girod (] ; born 16 January 1985) is an Argentine professional footballer who plays as a right back for West Ham United and the Argentina national team.  Zabaleta can operate on both sides of the pitch as a full back and is known for his tenacious style of play, and has captained his club on numerous occasions.

Martin Samuelsen: Martin Samuelsen (born 17 April 1997) is a Norwegian professional footballer who plays for West Ham United, and the Norway national team.  After long spells at the academies of Vard Haugesund and Manchester City and short trials at big clubs across Europe, Samuelsen signed for West Ham in June 2015.  Samuelsen, a versatile player, can play both central and wide midfield positions as well as a forward.  He went on loan at Peterborough United for the majority of the 2015-16 season.

Manuel Lanzini: Manuel Lanzini (born 15 February 1993) is an Argentine footballer who plays as an attacking midfielder for English club West Ham United and the Argentina national team.  He has previously played for River Plate and Fluminense.  He is described as possessing phenomenal dribbling ability, as well as fantastic acceleration and vision and the ability to ghost past defenders.  He is nicknamed "the jewel" ("la joya").

Sam Byram: Samuel Mark "Sam" Byram (born 16 September 1993) is an English professional footballer who plays for Premier League club West Ham United.  He primarily plays as a right back, but can also play as a right midfielder or right winger.

Freddie Sears: Frederick David "Freddie" Sears (born 27 November 1989) is an English professional footballer who plays as a forward for Ipswich Town.  He started his career with his local club West Ham United at the age of eleven, progressing through the West Ham United Academy.  He made a scoring first-team debut in March 2008 when he netted the winner against Blackburn Rovers after coming on as a second-half substitute.  Sears made over 50 first-team appearances for West Ham, but never held down a regular starting position.

Supporting paragraphs: Mariana Kovacevic Pablo Zabaleta
Answer: Asamoah Gyan