Which of these two act operas, Lucrezia Borgia or Il pirata, was based on a three-act melodrame? 
Il pirata: Il pirata ("The Pirate") is an opera in two acts by Vincenzo Bellini to an Italian libretto by Felice Romani which was based on a three-act mélodrame from 1826, "Bertram, ou le Pirate" ("Bertram, or The Pirate") by Charles Nodier and "Raimonde" (actually Isidore Justin Séverin Taylor).
i don't know