Answer:
A. To create sympathy for Kelly because of her actions.
Step-by-step explanation:
Dramatic irony is when the audience knows something that the characters in the story don't. In this case, it's that Kelly had heard Tashi and Ai talking about the party without them knowing, even though we, as the audience/readers, know.
You can automatically eliminate choices "C" and "D," since they don't make any sense. That leaves you with choices "A" and "B." There really isn't any suspense in this short story, so that eliminates answer "B."
As the audience learns of Kelly's actions and the consequences, we feel bad for her situation. (Which is answer, "A.")