You will review both quantitative and qualitative research. The topic is up to you as long as you choose a peer-reviewed, academic research piece. I suggest

choosing a topic that is at least in the same family as your expected dissertation topic so that you can start viewing what is out there. Consider also that

leadership is a major component of this program, so your topic should at least in part have that as a focus. You must submit original work, however, and a

paper that returns as a large percentage of copy/paste to other sources will not be accepted. You will see an example of a quantitative and qualitative piece