How does the author use irony to develop the theme of the poem?

Read the excerpt from julius caesar, act 5, scene 5. brutus. why this, volumnius. the ghost of caesar hath appeared to me two several times by night—at sardis once, and this last night, here in philippi fields. i know my hour is come. volumnius. not so, my lord. brutus. nay, i am sure it is, volumnius. thou seest the world, volumnius, how it goes. our enemies have beat us to the pit, [low alarums] it is more worthy to leap in ourselves than tarry till they push us. which prediction about the plot does this passage most support? brutus will replace caesar. brutus will take his own life. brutus will surrender to his enemies. brutus will be forever haunted by caesar.

For all of those, i want the answer. me.

What does the narrator do in this passage to increase suspense and encourage the reader to continue reading