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.
Structure of Poetry. Poetry is literature written in stanzas and lines that use rhythm to express feelings and ideas. Poets will pay particular attention to the length, placement, and grouping of lines and stanzas. ... Lines or whole stanzas can be rearranged in order to create a specific effect on the reader.
