Question Writer Manual/About Questions/Multiple Response
Multiple Response 
As with the multiple choice question, you enter a range of answers for the quiz taker to choose from. This time there can be more than one correct answer. Remember to tick all the answers that are correct. The quiz-taker only receives points if he selects all the answers that are correct - otherwise he gets no points. If you want to award points for a partially correct answer, use the Partial Credit question.