I'm not sure what slide type you are referring to when you mention Mastery Challenge, but you can add a drag and drop to just about any slide that contains objects that you would like to use for such an interaction. Here's a recent example of when I added a drag and drop into a slide that I designed for additional purposes.
Any drag and drop is a three-step process.
Hi Paul, I'm thrilled & honored to have you answer my question. I'm a big follower of your tutorials, they amazingly well done, informative, easy to follow & to the point. I tried making a Drag N Drop slide separately & moved it inside my Mastery Challenge Quiz section & I was able to include that as a part of that quiz. Earlier I was trying to insert a Question slide with Drag N Drop, but as you know, there's no such option from within the Question Slide. Thank you very much for your help!