Der Rosenkavalier (The Knight of the Rose or The Rose-Bearer), Op. 59, is a comic opera in three acts by Richard Strauss to an original German libretto by Hugo von Hofmannsthal.
 It is loosely adapted from the novel "Les amours du chevalier de Faublas" by Louvet de Couvrai and Molière’s comedy "Monsieur de Pourceaugnac".
 It was first performed at the Königliches Opernhaus in Dresden on 26 January 1911 under the direction of Max Reinhardt, Ernst von Schuch conducting.
 Until the premiere the working title was "Ochs von Lerchenau".
 (The choice of the name Ochs is not accidental, for in German Ochs means ox, which depicts the character of the Baron throughout the opera.)
Ivan Allen (June 29, 1930 – May 7, 2012) was an American ballet dancer who was active as a principal dancer with the American Ballet Theatre during the 1950s and early 1960s.
 He became a principal soloist with the Metropolitan Opera in 1964, making his debut with the company in Jules Massenet's "Manon" on November 18, 1964.
 He appeared with the company 288 times over the next 14 years, making his last appearance on January 12, 1978 in Richard Strauss's "Der Rosenkavalier".
Delores Ziegler (born 4 September 1951) is an American mezzo-soprano who has had an active international performance career since the late 1970s.
 A former resident artist at the Cologne Opera, she has performed leading roles with many of the world's best opera houses, including La Scala, the Lyric Opera of Chicago, the Metropolitan Opera, the San Francisco Opera, and the Vienna State Opera.
 She is currently a professor of voice at the University of Maryland.
 While she has performed a broad repertoire, she is widely admired for her performances in operas by Wolfgang Amadeus Mozart and Richard Strauss; particularly Cherubino in "The Marriage of Figaro", Dorabella in "Così fan tutte", Idamante in "Idomeneo", and Octavian in "Der Rosenkavalier".
Ellen Shade is an American operatic soprano from New York.
 Her repertoire includes the Kaiserin in "Die Frau ohne Schatten", the Marschallin "Der Rosenkavalier", Chrysothemis "Elektra", Ariadne "Ariadne auf Naxos", Arabella, Katya Kabanova, Aida, Desdemona "Otello", Amelia "Un ballo in Maschera", Amelia "Simon Boccanegra", Sieglinde "Die Walkure", Elsa "Lohengrin", Elisabeth "Tannhauser", Eva "Die Meistersinger von Nurnberg".
 In Europe she has appeared at La Scala Milan, the Royal Opera House, Covent Garden, the Bastille and the Chatelet in Paris and in Vienna, Salzburg Festival, Berlin, Hamburg, Frankfurt [Article Reference], Stuttgart, Amsterdam, Brussels, Geneva and Athens.
 In North America she has performed with virtually all the major opera companies, including the Metropolitan Opera New York, Chicago, San Francisco, Los Angeles, Houston, Dallas, Seattle, Santa Fe, and the Canadian Opera in Toronto.
Renée Fleming (born February 14, 1959) is an American opera singer and soprano whose repertoire encompasses Richard Strauss, Mozart, Handel, bel canto, lieder, French opera and chansons, jazz and indie rock.
 Fleming has a full lyric soprano voice.
 She has performed coloratura, lyric, and lighter spinto soprano operatic roles in Italian, German, French, Czech, and Russian, aside from her native English.
 She also speaks fluent German and French, along with limited Italian.
 Her signature roles include Countess Almaviva in Mozart's "Le nozze di Figaro", Desdemona in Verdi's "Otello", Violetta in Verdi's "La traviata", the title role in Dvořák's "Rusalka", the title role in Massenet's "Manon", the title role in Massenet's "Thaïs", the title role in Richard Strauss's "Arabella", the Marschallin in "Der Rosenkavalier", and the Countess in "Capriccio".
Norine Burgess is a Canadian singer.
 She is a graduate of the University of Calgary and the University of Toronto’s Opera School, mezzo-soprano.
 She received additional training as a member of the Canadian Opera Company (COC) Ensemble where she appeared in Electra, Suor Angelica, Lulu and Der Rosenkavalier.
 Ms. Burgess also performed Le Nozze di Figaro(Cherubino), Ariadne auf Naxos (Dryad), La Traviata(Flora) and Die Zauberflöte (Second Lady) with the COC.
 Additional operatic successes include Le Nozze di Figaro (Cherubino) and Carmen (Mercedes) with the Vancouver Opera, Fenena in Nabucco with Manitoba Opera, Albert Herring (Nancy) with the Calgary Opera and many appearances with the Edmonton Opera.
Otto Edelmann (February 5, 1917 in Vienna – May 14, 2003 in Vienna) was an Austrian bass.
 He was born in Vienna and studied singing in Vienna with Gunnar Graarud.
 His debut was at Gera as Figaro in Mozart's "The Marriage of Figaro".
 He later sang the Vienna State Opera, the Edinburgh Festival and the Metropolitan Opera.
 He sang at the Bayreuth Festival immediately after its reopening in 1951 after World War II, performing the role of Hans Sachs in Wagner's "Die Meistersinger von Nürnberg".
 (He also recorded as Veit Pogner the goldsmith in the same work in one of Hans Knappertsbusch's early recorded performances.)
 He also sang Ochs in Richard Strauss's "Der Rosenkavalier" at the first performances in the new Salzburg Festspielhaus in 1960.
 In 1957, he recorded the role of Wotan opposite Kirsten Flagstad in Georg Solti's recording of Act III of Wagner's "Die Walküre" (an album made prior to the later famous complete set of "Der Ring des Nibelungen").
 He died in Vienna.
Manon (] ) is an "opéra comique" in five acts by Jules Massenet to a French libretto by Henri Meilhac and Philippe Gille, based on the 1731 novel "L’histoire du chevalier des Grieux et de Manon Lescaut" by the Abbé Prévost.
 It was first performed at the Opéra-Comique in Paris on 19 January 1884, with sets designed by Eugène Carpezat (Act I), Auguste-Alfred Rubé and Philippe Chaperon (Acts II and III), and Jean-Baptiste Lavastre (Act IV).
Peter Klein (January 25, 1907 – October 3, 1992) was a German lyric and light-operatic tenor.
 He was born in Zühndorf (near Cologne), and died in Vienna.
 He achieved the prestigious rank of Kammersänger.
 Beginning in 1942, he sang at the Vienna State Opera, and performed in several Salzburg Festivals.
 He made his debut at New York's Metropolitan Opera on 21 November 1949 as Valzacchi in "Der Rosenkavalier" and sang there for three seasons in roles including Don Basilio in "Le nozze di Figaro", Mime in "Siegfried", and Jaquino in "Fidelio".
 In 1956, he was hired as professor at the Konservatorium der Stadt Wien.
Derek Hammond-Stroud, OBE (10 January 192614 May 2012) was an English baritone opera singer best known for his performances of German lieder and his international performances in opera, particularly the roles of Alberich in Wagner's "Der Ring des Nibelungen", Herr Faninal in "Der Rosenkavalier" and Beckmesser in "Die Meistersinger von Nürnberg".
 He also made recordings, including a series of recordings of the Gilbert and Sullivan patter roles.

Question: Which opera has more acts, Der Rosenkavalier or Manon? 
Answer: Manon