The PA Program Admissions Committee wants to know that you have thought through all options and scenarios if you do not earn acceptance this cycle. Your answer to this question should show the Admissions Committee that your interest in a career as a Physician's Assistant goes deeper than your immediate acceptance into their school.
If you are not accepted, express that it will not be the end of your journey. Perhaps you would take the time to upgrade, apply to new schools, or entertain a different path within the medical field. Alternatively, you can let the Admissions Committee know that one rejection won't stop you. Talk about your plan to qualify better and reapply when ready. Whichever way you respond, show admissions that you have the confidence and drive to achieve your goals.