question: Which opera, Iphigénie en Aulide or Lulu,  is an opera in three acts by Alban Berg"?
answer: Lulu
context: Title: Magdaléna Hajóssyová
  Passage: Magdaléna Hajóssyová (born 25 July 1946, Bratislava) is a classical Slovak soprano who has had an active international career singing in operas, concerts, and recitals since the late 1960s.  She has been particularly active at the Prague State Opera where she has been a principal artist since 1972.  She has also had a long and fruitful partnership with the Berlin State Opera beginning in 1975.  In 1977, 1981, and 1987, she won the Berlin Critic's Prize for her portrayal of the roles of Margarete in Charles Gounod's "Faust", the Elektra in Mozart's "Idomeneo", Carl Maria von Weber's "Euryanthe", and Christoph Willibald Gluck's "Iphigénie en Aulide".
  Title: Iphigénie en Aulide
  Passage: Iphigénie en Aulide ("Iphigeneia in Aulis") is an opera in three acts by Christoph Willibald Gluck, the first work he wrote for the Paris stage.  The libretto was written by François-Louis Gand Le Bland Du Roullet and was based on Jean Racine's tragedy "Iphigénie".  It was premiered on 19 April 1774 by the Paris Opéra in the second Salle du Palais-Royal and revived in a slightly revised version the following year.
  Title: Lulu (opera)
  Passage: Lulu (composed from 1929–1935, premièred incomplete in 1937 and complete in 1979) is an opera in three acts by Alban Berg.  The German-language libretto was adapted by Berg himself from Frank Wedekind's two "Lulu" plays, "Erdgeist" ("Earth Spirit", 1895) and "Die Büchse der Pandora" ("Pandora's Box", 1904).  Berg died before completing the third and final act, and in the following decades, the opera was typically performed incomplete.  Since its publication in 1979, however, the Friedrich Cerha orchestration has become popular.  Theodor W. Adorno wrote "The opera "Lulu" is one of those works that reveals the extent of its quality the longer and more deeply one immerses oneself in it."
  Title: Iphigénie en Tauride (Desmarets and Campra)
  Passage: Iphigénie en Tauride (English: "Iphigeneia in Tauris") is an opera by the French composers Henri Desmarets and André Campra.  It takes the form of a "tragédie en musique" in a prologue and five acts.  The libretto is by Joseph-François Duché de Vancy with additions by Antoine Danchet.  Desmarets had begun work on the opera around 1696 but abandoned it when he was forced to go into exile in 1699.  Campra and his regular librettist Danchet took up the piece and wrote the prologue, most of Act Five, two arias in Act One, an aria for Acts Two and Three, and two arias for the fourth act.  The plot is ultimately based on Euripides' tragedy "Iphigeneia in Tauris".
  Title: François-Louis Gand Le Bland Du Roullet
  Passage: François-Louis Gand Le Bland Du Roullet (10 April 1716 in Normanville – 2 August 1786 in Paris) was a French diplomat and playwright.  He is chiefly remembered today as the librettist of Gluck's operas "Iphigénie en Aulide" and "Alceste" (1776 French version).  He also co-wrote (with Louis-Théodore de Tschudi) the libretto for Salieri's opera "Les Danaïdes".
  Title: Wozzeck
  Passage: Wozzeck (] ) is the first opera by the Austrian composer Alban Berg.  It was composed between 1914 and 1922 and first performed in 1925.  The opera is based on the drama "Woyzeck", which was left incomplete by the German playwright Georg Büchner at his death.  Berg attended the first production in Vienna of Büchner's play on 5 May 1914, and knew at once that he wanted to base an opera on it.  From the fragments of unordered scenes left by Büchner, Berg selected fifteen to form a compact structure of three acts with five scenes each.  He adapted the libretto himself, retaining "the essential character of the play, with its many short scenes, its abrupt and sometimes brutal language, and its stark, if haunted, realism..."
citations: Iphigénie en Aulide Lulu (opera)