The correct answer is D. opera. Song cycles were never particularly popular or frequently composed in Italy. Concertos and symphonies were written, but not cultivated and nourished. Opera is the most Italian of all art forms, and the 19th century was its golden age, when all the great romantic composers (Bellini, Donizetti, Rossini, Verdi and many more) wrote operas, conducted them, and built them into the nascent Italian national identity.