When a school is selecting their future student body, they'll be looking for those who consider their institution as the best, and exhibit it was their top choice. It exhibits poor planning to put all your eggs in one basket. It's expected for you to play the numbers game. So this question is assessing your planning and your preference. If Brody School of Medicine is tied with another school of choice, feel free to let them know. Showcase the research you've performed on both institutions and ask them why they feel Brody School of Medicine stands apart from your other top choice. Let them sell you on why their school is the best. Exhibit enthusiasm and let them convince you that they are your top choice.