We have a department that has many multiple choice quesions with multiple answers, but they don't want to give any credit for the answer unless the student selects all of the correct answers.
We tried setting the incorrect answers to -100%, and that worked somtimes, although not when the students selected some correct answers (but not all of them) and no incorrect answers. That still resulted in partial points instead of no points for that question.
Any suggestions on how to make multiple choice with multiple correct answers not give partial credit would be appreciated.