I get that but as already explained for this user (also available in the file description and in a plenty of posts in this topic), this app uses one type of quiz (graded mode) that requires at least one right and one wrong answers. Also is said in this same topics, and again, for him, that new type of quizzes will come in a future version.
It's recommend to read the file description, the support topic and if still have doubts, make pre-sales questions. None of this happened. But when things starts to derail, well, I just put on ignore and life goes on... it means absolutely nothing to me.