Show that you are prepared for the interview by having an immediate answer. The only wrong answer here is simply, "I don't know." In most interviews, you will get one or two personal questions to see how you present yourself. You want to be able to articulate yourself well, responding politely and even passionately when appropriate. A good way to respond to this question is by sharing about a person who has been a positive influence on you and your career. If your dad motivated you to push through to finish your education, talk about how that impacted you. Who showed you that it was possible to overcome even the greatest obstacles? Who taught you the skills that brought you where you are today?