To create a game or activity where only one drop zone is the correct answer, first add all your planned drop zones (correct answer and incorrect answer zones). Once all the zones are added, wire each draggable item to only its single correct drop zone (click and drag the blue hand icon of the draggable element to the blue flag icon of the drop zone to create this wire). The other drop zones which are not wired will automatically be scored as incorrect answers for that draggable item. 

Do not mark any of the drop zones as correct or incorrect answers or your deck will complain that students have not found all the correct answers. Draggable elements are set to be a correct answer by indication of this blue wire. It is possible for a drop zone to require multiple correct answers, by creating wires from multiple draggable elements to the same drop zone.