The answer is 'by not fulfilling expectations'. The other options don't really surprise the reader, and if the plot is going into one direction, and then what you'd expect to happen doesn't actually happen, you are surprised, and the element of irony is achieved.
Answer:
Beth no longer wanted to live at home
Explanation:
Macbeth knows that Birnam Wood is approaching and his end is near
C is the answer your looking for
