Explain dramatic irony from unequal knowledge

READ THE PASSAGE

A narrator explains that an invitation for the upstairs neighbor slips under Ari’s door. Ari reads it and says, “At last, they chose me to lead the expedition.”

Which difference in knowledge matters here?

1. Readers have never seen the note.
2. Readers know the note was misdelivered; Ari believes it was meant for Ari.
3. Ari and the reader know the intended recipient.
4. The note states that all recipients are the same person.

A little hint: Compare what the reader knows with what the character believes; explain the tension produced by that gap.