I would cast my vote with Jerry & the rest for #13 background as being the least intrusive/distractive and making it easiest to stay focused on the subject matter.

As an aside, rubbing a scratch with the meat of a raw pecan or black walnut will hide it quite well, usually completely from the naked eye, and will have zero effect on the original finish. I've used pecans mostly for that task. The remedy was shown me by a furniture finisher who dealt with highly polished furniture like dining room table tops and such. Pretty amazing instant result too. I have no experience whether it would hide a scratch from a camera, but I don't see why it would not.