I created a sample that uses straight Lectora actions and the feedback settings on the question. This all depends on whether you have a submit button used for the question.
It’s setup so that clicking the submit button verifies that the question does not contain “na” OR “is not empty” before processing it. You want to make sure the user doesn’t get the feedback if they haven’t moved any of the drop items.
In this sample, the Feedback on the question is used to run an action group for both correct/incorrect, since it sounds like you provide the correct/incorrect feedback along with other actions as part of that group. Hope this helps, too!