Vonnegut creates irony by showing that Hazel cannot remember her son's death or why she has tears on her face, as shown in option C.
Vonnegut features irony when Hazel cannot remember her son's death or why she has tears on her face. This is because the forgetfulness presented by her represents indifference and a lack of sentimentality regarding the death of her son.
This is reinforced when she doesn't know why she is crying and it is at this point that the irony sets in more strongly, as she is crying over her son's death.
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https://brainly.com/question/2893936