Wie heißt das österreichische Parlament?

Why this is the correct answer

Austria's parliament consists of two chambers: the Nationalrat, which is the primary legislative chamber elected directly by citizens, and the Bundesrat, which represents the nine Bundesländer at the federal level. Laws are generally passed by the Nationalrat, while the Bundesrat can review and in some cases object to legislation. Together they form the bicameral parliamentary system of the republic.