Question: Which director is American, Mark L. Lester or Ken Loach?

full_context: Document 1: Poor Cow: Poor Cow is a 1967 British drama film, directed by Ken Loach and based on Nell Dunn's novel of the same name. It was Ken Loach's first feature film, after a series of successful TV productions.
Document 2: Home for Life: Home for Life, the founding documentary of Kartemquin Films released in 1967, depicts the experiences of two elderly people in their first month at a home for the aged. One is a woman whose struggle to remain useful in her son and daughter-in-law's home is no longer appreciated. The other is a widower, without a family, who suddenly realizes he can no longer take care of himself. The film offers an unblinking look at the feelings of the two new residents in their encounters with other residents, medical staff, social workers, psychiatrists and family. A touching, sometimes painfully honest dramatic experience, it is valuable for in-service staff training, and for all other audiences both professional and non-professional, interested in the problems of the aged.
Document 3: Mark Steven Johnson: Mark Steven Johnson (born October 30, 1964) is an American screenwriter, film director, and producer.
Document 4: Ken Loach: Kenneth Charles Loach (born 17 June 1936) is an English director of television and independent film. He is known for his socially critical directing style and for his socialist ideals, which are evident in his film treatment of social issues such as poverty ("Poor Cow", 1967), homelessness ("Cathy Come Home", 1966) and labour rights ("Riff-Raff", 1991, and "The Navigators", 2001).
Document 5: The Spirit of '45: The Spirit of '45 is a 2013 documentary film by British director Ken Loach, focused on and celebrating the radical changes in postwar Britain under the Labour government of Clement Attlee, which came to power in 1945. Relying primarily on archive footage and interviews, and without a narrative voiceover, the film recounts the endemic poverty in prewar Britain, the sense of optimism that followed victory in World War II and the subsequent expansion of the welfare state, founding of the National Health Service and nationalisation of significant parts of the UK's economy. The film documents the extent to which these achievements, as Loach sees them, have since been subject to attack in the decades that followed, particularly under the Conservative governments of Margaret Thatcher in the 1980s. Loach said that the model for the film was "oral history, with pictures".
Document 6: Sean S. Cunningham: Sean Sexton Cunningham (born December 1, 1941) is an American film director, producer, and writer.
Document 7: Mike Leigh: Mike Leigh OBE (born 20 February 1943) is an English writer and director of film and theatre. He studied at the Royal Academy of Dramatic Art (RADA) before honing his directing skills at East 15 Acting School and further at the Camberwell School of Art and the Central School of Art and Design. He began as a theatre director and playwright in the mid-1960s. In the 1970s and 1980s his career moved between theatre work and making films for BBC Television, many of which were characterised by a gritty "kitchen sink realism" style. His well-known films include the comedy-dramas "Life is Sweet" (1990) and "Career Girls" (1997), the Gilbert and Sullivan biographical film "Topsy-Turvy" (1999), and the bleak working-class drama "All or Nothing" (2002). His most notable works are the black comedy-drama "Naked" (1993), for which he won the Best Director Award at Cannes, the Oscar-nominated, BAFTA and Palme d'Or-winning drama "Secrets & Lies" (1996), the Golden Lion winning working-class drama "Vera Drake" (2004), and the Palme d'Or nominated biopic "Mr. Turner" (2014). Some of his notable stage plays include "Smelling A Rat", "It's A Great Big Shame", "Greek Tragedy", "Goose-Pimples", "Ecstasy", and "Abigail's Party".
Document 8: John Landis: John David Landis (born August 3, 1950) is an American film director, screenwriter, actor, and producer. He is best known for the comedy films that he has directed such as "National Lampoon's Animal House" (1978), "The Blues Brothers" (1980), "An American Werewolf in London" (1981), "Trading Places" (1983), "¡Three Amigos!" (1986), "Coming to America" (1988) and "Beverly Hills Cop III" (1994), and for directing Michael Jackson's music videos for "Thriller" (1983) and "Black or White" (1991).
Document 9: Mark W. Ryan: Mark W. Ryan is an award-winning music editor for film and television, currently living in Los Angeles, California. A two-time winner of the Motion Picture Sound Editors "Golden Reel Award", he has worked on films such as "Liar, Liar" as well as many primetime television and animation shows. Also a singer and songwriter and an accomplished guitarist, Ryan began his entertainment career as a drummer in his hometown of Cleveland, Ohio. He earned a B.A. in music theory and percussion from Kent State University in 1983, and married before relocating to Los Angeles in 1986. He is also credited as a voice-over actor in the 1991 animated series "Little Shop", based on the film "Little Shop Of Horrors", in which he voiced the character Paine Driller.
Document 10: Richard Lester: Richard Lester (born Richard Lester Liebman; January 19, 1932) is an American film director based in Britain. Lester is known for his work with the Beatles in the 1960s and his work on the "Superman" film series in the 1980s.
Document 11: Richard Rush (director): Richard Rush (born April 15, 1929 in New York, New York) is an American movie director, scriptwriter, and producer. He is best known for the Oscar-nominated "The Stunt Man". His other works, however, have been less celebrated. The next best-known of his movies is "Color of Night" — also nominated, but in this case for the Golden Raspberry Award. Rush also directed "Freebie and the Bean", an over-the-top police buddy comedy/drama starring Alan Arkin and James Caan. He co-wrote the screenplay for the 1990 movie "Air America".
Document 12: The End of Arthur's Marriage: The End of Arthur's Marriage is a television satirical musical drama that was episode in "The Wednesday Play" series first broadcast on 17 November 1965. It was an early work of director Ken Loach, and the script was written by poet Christopher Logue. It is unusual in Loach's catalogue for the surrealism, and the director later said that he believed himself to have been "the wrong man for the job". Main actor Ken Jones had previously worked with Loach on "Wear a Very Big Hat" and "3 Clear Sundays", and later featured in the controversial 1969 play "The Big Flame".
Document 13: Roller Boogie: Roller Boogie is a 1979 American romantic musical drama film starring Linda Blair and introducing Jim Bray, a former competitive artistic skater from California. The film also stars Beverly Garland, Mark Goddard, and Kimberly Beck, and is directed by Mark L. Lester.
Document 14: Jim Loach: James Loach (born 6 June 1969) is an English film director. He is the son of the film director Ken Loach.
Document 15: Mark L. Lester: Mark L. Lester (born November 26, 1946) is an American film director, screenwriter, and producer. He is best known as a prolific director of cult films including the disco musical "Roller Boogie", the vigilante thriller film "Class of 1984", the Stephen King-adaptation "Firestarter" (1984), the Arnold Schwarzenegger action film "Commando" (1985), and the action-comedy "Armed and Dangerous" (1986), starring John Candy, Eugene Levy, and Meg Ryan.
ground_truth: Mark L. Lester