Captivate 8 - Can Drag and Drop show correct answer after submit?

If you're NOT trying to use HTML5, the Infosemantics drag and drop lite question widget might be a good way to solve your issue. 

Unlike the default Captivate drag and drop interaction it DOES give you the option of showing the correct answer during Quiz Review.  You just add another caption to the slide that will ONLY be visible during quiz review.  When the learner mouses over this object during the quiz review the drag objects will animate and move to the correct positions.  Very cool. But as I mentioned above...not for HTML5,

No, D&D is a hybrid slide, not totally behaving like a Question slide. That means that also during Review it will never show the correct solution. You could log a feature request.

Indeed, you could create another slide with the correct solution, and solve with custom navigation. The D&D slide will always be reset if you leave it and come back to it.