It was marked correct but said [The][Unsullied][are][n't][stopping] had a typo in it, and it should be "are not," rather than "aren't."
I've flagged this so hopefully it'll be corrected. It was an exercise where you choose word bubbles so [n't] shouldn't be an option if they wanted something specific.
I don't understand what's wrong here. Both "are not" and "aren't" are fine in English, and should both be accepted, and it sounds like they both are being accepted. What's the issue?