Question: Six chansons pour piano was by the composer who became a naturalized citizen of what country?

full_context: Document 1: George Antheil: George Antheil ( ; July 8, 1900 – February 12, 1959) was an American avant-garde composer, pianist, author and inventor whose modernist musical compositions explored the modern sounds – musical, industrial, mechanical – of the early 20th century.
Document 2: Sonatas and Interludes: Sonatas and Interludes is a collection of twenty pieces for prepared piano by American avant-garde composer John Cage (1912–1992). It was composed in 1946–48, shortly after Cage's introduction to Indian philosophy and the teachings of art historian Ananda K. Coomaraswamy, both of which became major influences on the composer's later work. Significantly more complex than his other works for prepared piano, "Sonatas and Interludes" is generally recognized as one of Cage's finest achievements.
Document 3: Chant de Linos: Chant de Linos is a work for flute and piano written by French composer André Jolivet in 1944 as a commission for a Paris Conservatoire competition which was subsequently won by Jean-Pierre Rampal. He transcribed it for flute, violin, viola, cello and harp the same year. The piece has since become a staple of the modern flute repertoire.
Document 4: Pierre Boulez: Pierre Louis Joseph Boulez CBE (] ; 26 March 1925 – 5 January 2016) was a French composer, conductor, writer and organiser of institutions. He was one of the dominant figures of the post-war classical music world.
Document 5: Four Anniversaries for the Piano: The piano composition Four Anniversaries was composed in 1948 by American composer Leonard Bernstein and consists of four movements, each written for a different person in Bernstein’s life. Leonard Bernstein composed four other works using the same concept: "Seven Anniversaries" (1943), "Five Anniversaries" (1948–1951), "Two Anniversaries" (1965), and "Thirteen Anniversaries" (1988). Each movement celebrates the birthday of a different individual, such as Serge Koussevitzky, Paul Bowles, William Schuman, Stephen Sondheim, and Aaron Copland. The "Four Anniversaries" are dedicated to Felicia Montealegre, Johnny Mehegan, David Diamond, and Helen Coates.
Document 6: Les Six: "Les Six" (] ) is a name given to a group of six French composers who worked in Montparnasse. The name, inspired by Mily Balakirev's "The Five", originates in critic Henri Collet's 1920 article "Les cinq Russes, les six Français et M. Satie " ("", 16 January 1920). Their music is often seen as a reaction against the musical style of Richard Wagner and the impressionist music of Claude Debussy and Maurice Ravel.
Document 7: Six chansons pour piano: Six chansons pour piano is a short piano suite and one of the earliest completed compositions by French composer Iannis Xenakis. It was composed between 1950 and 1951 and dedicated to Bernard Le Floc'h.
Document 8: Iannis Xenakis: Iannis Xenakis (Greek: Γιάννης (Ιάννης) Ξενάκης ] ; 29 May 1922 – 4 February 2001) was a Romanian-born, Greek-French composer, music theorist, architect, and engineer. After 1947, he fled Greece, becoming a naturalized citizen of France. He is considered an important post-World War II composer whose works helped revolutionize 20th century classical music.
Document 9: Yanni: Yiannis Chryssomallis (Greek: Γιάννης Χρυσομάλλης , "Giánnis Chrysomállis"; born November 14, 1954), known professionally as Yanni ( ), is a Greek keyboardist, composer, and record producer. Born and raised in Kalamata, Greece, he developed an interest in music at an early age and taught himself the piano, learning his own style of musical notation. He became a competitive swimmer as a teenager and set a national record at 14.
Document 10: Edgard Varèse: Edgard Victor Achille Charles Varèse (] ; also spelled Edgar Varèse; December 22, 1883 – November 6, 1965) was a French-born composer who spent the greater part of his career in the United States.
Document 11: Pour le piano: Pour le piano ("For the piano"), L.95, is a suite for solo piano by Claude Debussy. The composition was finished and issued in 1901. Its premiere took place on 11 January 1902 in the Salle Érard for the Société Nationale de Musique, with Ricardo Viñes as the pianist.
Document 12: ST-X Ensemble: The ST-X Ensemble is an American ensemble dedicated to performing the music of Iannis Xenakis. It was formed in New York City in 1994 by the conductor Charles Zachary Bornstein, who had served as an assistant conductor to Leopold Stokowski, and was the last private student of the Austrian musical conductor Hans Swarowsky. He formed the music to promote performances of Xenakis's music in the United States after learning that most of the performances of that composer's music took place outside the United States.
Document 13: Preludes (Messiaen): Préludes pour piano ("Preludes for piano") is an early work for piano by the French composer Olivier Messiaen composed in 1928–1929, when the composer was 20 years old. Messiaen considered it to be his first work of any value. The composition is based on Messiaen's modes of limited transposition, and betrays an influence of Debussy's preludes.
Document 14: Jean-Max Albert: Jean-Max Albert is a painter, sculptor, writer, and musician. He has published theory, artist's books, a collection of poems, plays and novels inspired by quantic physics. He perpetuated a reflexion initiated by Paul Klee and Edgar Varèse on the transposition of musical structures into formal constructions. He created plant architectures which come close to site-specific art, environmental sculpture and generative art.
Document 15: Six épigraphes antiques: Six épigraphes antiques, L. 131, is a suite of six pieces by Claude Debussy, originally written for piano duo. Completed in July 1914, the suite was Debussy's only completed composition that year. In 1915 Debussy transcribed them for piano solo. Much of the music (over 100 measures) is taken from the musical accompaniments he had written in 1901 for his friend Pierre Louÿs's erotic lesbian poems "Les Chansons de Bilitis".
ground_truth: France