Which sentence below shows correct use of em dashes? (4 points)

By the end-of-the-story, no one could believe it the main-character, was dead.

By - the end of the story no one could believe it, the main - character was dead.

By the end of the story, no-one could believe it the main, character - was dead.

By the end of the story-no one could believe it-the main character was dead.