I think this direction has promise, but I foresee some problems and would very much like your continued advice.
(1.) Dragging the labels to the diagram - For the most part, this type of question will have maybe 10 drops. A complication comes because user may drop drag1 onto target1 and get a point, and continue with drag2 through drag10 correctly, and then change his/her mind and move drag1 onto target10 and drag10 onto target1. So the variable "answers" would have to subtract a point when the correct drag is removed. That complicates the trigger design, no?
(2.) The same question design will be reused for all ten (or more) of these drag-n-drop questions in the given quiz. So the variable "answers" needs to be reset to zero when the slide is activated, no? Or do there need to be ten (or more) variables, answers1, answers2 and so on?