Opera Quiz No.1

I am also introducing an opera quiz. Every time I make a new entry, you will find a question with four possible solutions. The correct answer will be given with the next entry. All questions and answers are from the "Experten Quiz: Oper" by NGV. 


Question No. 1:


Which of the following works by Jacques Offenbach is considered his only opera?
a. Orphee aux enfers
b. La vie parisienne
c. Barbe-bleue
d. Les contes d'Hoffmann