Question: Who is a Bulgarian operatic soprano that had their career launched by The World Opera Competition? 
Sentence (from "Operalia, The World Opera Competition"): Founded in 1993 by Plácido Domingo, the competition has helped launch the careers of several important artists, such as Joseph Calleja, Giuseppe Filianoti, Rolando Villazón, José Cura, Joyce DiDonato, Elizabeth Futral, Inva Mula, Ana María Martínez and Sonya Yoncheva.
Relevant evidence: Yes