Definition: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it, i.e., the proper nouns in the passage. Your job is to determine whether information from more than one term is needed to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: Which of Wagner's operas that Cavelti starred in was written first? Passage:In 1944, she returned to Switzerland, singing as the leading dramatic contralto at the Opernhaus Zürich. She appeared as Brangäne in Wagner's Tristan und Isolde, as Fricka in his Die Walküre, as Ortrud in his Lohengrin, and in the title role (Octavian) of Der Rosenkavalier by Richard Strauss, among others. In 1949, she took part in the premiere of Willy Burkhard's Die schwarze Spinne. The same year, she performed in Monteverdi's L'incoronazione di Poppea, both at Vicenza's Teatro Olimpico and at La Fenice in Venice. She performed as a guest at La Scala in Milan several times, including Octavian, Brangäne, Venus in Wagner's Tannhäuser, and the title role of Honegger's Judith. She appeared as a guest at the Vienna State Opera, in Belgium, France, United Kingdom, in Argentina, and the US.


a