In the prologue to Romeo and Juliet, the chorus sets the scene. It provides useful background information concerning the long-running feud between the Montagues and the Capulets. Not only that, it also tells us that Romeo and Juliet, the star-cross'd lovers, will tragically die.
What best explains the irony in the ending of "The Inchcape Rock" is option C:Sir Ralph removed the bell, hoping that other ships crash as a result. However, his own ship was destroyed due to the missing bell.