The best answer is:
It presents information to the reader that the characters do not yet know.
In the passage, Chandra believes she is about to receive an acceptance or rejection letter, but instead, she simply gets confirmation that her application has been received and that she will have to wait several weeks for a decision. This creates irony because the reader knows that the anticipation is unnecessary at this point, highlighting the disconnect between Chandra's expectation and the actual content of the letter.