Question: Six chansons pour piano was by the composer who became a naturalized citizen of what country?
Context: Air à boire is a French term which was used between the mid-17th and mid-18th centuries for a "drinking song".  These were generally strophic, syllabic songs to light texts.  Its predecessor was "chanson pour boire", the difference being mainly that "chansons pour boire" were for one voice with lute accompaniment, whereas "airs à boire" are generally for more than one voice. 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. 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. The Piano Sonata, sometimes also referred to as Sonata for Piano or in its original French form, Sonate pour piano, is a 1924 piano sonata by Russian composer Igor Stravinsky. 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. Chansons Pour Toutes Sortes de Monde is a 1990 album by Canadian songwriter Plume Latraverse. Chansons pour les mois d'hiver is francophone Canadian pop singer Isabelle Boulay's seventh studio album, released in November 2009.  It was certified gold in January 2010 as a result of selling 40,000 copies. Chansons pour les pieds was a 2001 album by Jean-Jacques Goldman sung in French.  The album was recorded at the Théâtre du Cratère d'Alès by Eric Van de Hel and Gildas Lointier, assisted by Renaud Van Welden.  All songs were written by the singer himself.  Released by JRG, the album met smash success on the charts : it topped the French and Belgian Albums Charts and remained charted for almost two years, and was #2 in Switzerland.  As the title ("Songs for the Dance") suggests, all the tracks are devoted to dance and represent music styles (canon chorale, gigue, technoriental, slow, tarentelle, R&B, ballad, disco, rock, slow zouk, fanfare swing, pop). Luxembourg was represented by well-known German singer Jürgen Marcus, with the song 'Chansons pour ceux qui s'aiment", at the 1976 Eurovision Song Contest, which took place on 3 April in The Hague.  For the first time ever, broadcaster RTL organised a public national final rather than their usual method of internal selection.  Marcus was the first German singer to represent Luxembourg, as their 1974 representative Ireen Sheer, although German-based, was British by birth. Chanson pour boire is a term for a French drinking song, frequently coupled with "chanson pour danser" (or "song for dancing").  It was used in from about 1627–1670.  It is different from the "air à boire" primarily by the period the term was used, and that "chansons pour boire" are usually for one voice with lute accompaniment, and "airs à boire" are for multiple voices with lute accompaniment.  Both are fairly simple; strophic, with syllabic settings of light texts.  The texts are usually about drinking and are humorous.
Answer: France