Hi Debra, yeah I see what you mean. I just tried it the responses dont actually disappear - they appear IN FRONT of the other options.
But thats academic to some degree, because whatever the reason, the end result is its no good!
To try to come up with another workaround for you, I downloaded your STORY file and tried out a few things here, but alas, nothing worked. It feels like the in-built mechanics of this question are fighting against us when we are trying to manually reset it.
To be honest, I hate these horrible matching drag and drop interactions, and have never liked how they both looked and operated.
Because of that, and this reset problem, I might suggest you instead go for a FREEFORM DRAG AND DROP interaction instead. This will absolutely give you what you want, and you can reset it perfectly to perform and look just right for your students.
If you havent done a Freeform question before, its nothing to be daunted by. Just build the slide visuals first, then go to INSERT > CONVERT TO FREEFORM, and finally in Form View, just tell Storyline which items are draggable, and where they should be dropped when correct.
Thats it, Storyline will handle the rest, and the little trigger you did earlier to reset (ie. Jump to slide This Slide...) will work perfectly.
Does this help at all?
P.S. I think you replied to my previous post using your email, so now all your personal contact details are shown in this forum! You probably want to edit that post and remove those details :)