Was ist die Hauptstadt des Bundeslandes Salzburg?

Why this is the correct answer

Salzburg, founded as a Roman settlement called Iuvavum, became the seat of a powerful prince-archbishopric in the medieval period. Today it is both the capital of the federal state of Salzburg and a UNESCO World Heritage city celebrated for its Baroque architecture and association with Wolfgang Amadeus Mozart. With around 155,000 inhabitants, it is Austria's fourth-largest city.