Have drop zone accept only one element out of several correct ones
I've recently been confronted with the following situation, which has currently no solution in the Drag & Drop activity.
In a certain drop zone DZ0 I need to accept as correct one out of two draggable elements, E1 and E2.
If I set that drop zone to "This drop zone can only contain one element", I can drag either E1 or E2 into that zone, not more than one, of course. But then, the total score for the activity expects 2 elements to be dragged into drop zone DZ0. When only one element has been dragged, it's impossible to achieve a full correct score.
I would like the score for that kind of drop zone to count for 1 point only, not 2.
I hope this makes sense.