For that area of an interview, or even for any question, I think the way you deliver your answer is more important that the answer itself. If you are an easy talker with good communication skills, just say anything because it gives you freedom to show your charisma. If you struggle to think on the spot, you can use the time to say something like "well I just wanted to thank you again for the chance to be here and for your time" of something along those lines. In either case you don't look like a blank-headed dude but also have the chance to emphasize your strength or minimize your weakness.