This question doesn't have one correct answer; think about a few qualities that you believe are your strengths. Once you two or three, think of an example for each of them. You don't have to talk about all of the qualities you came up with, pick the one with the best example and use that for your answer.

The interviewer wants you to brag a little about yourself here and talk about what you'll bring to the center. You don't need to go over the top, but talk about something that makes you proud.