I actually only got the Clinton one because of the information about the wives. I know his last name at birth was Blythe, not Clinton, so I figured maybe it was related to this guy having multiple wives or something. Looks from Wikipedia like my reasoning was wrong, but it's the reason I chose the right answer.
Never heard of peyton manning, let alone his dad. Heard all of all the others though, but for Norah Jones only by mention. (And couldn't pick mitt romney out of a line-up either)
I was today years old when I learned that Teddy Roosevelt wasn't FDR's father. I always just assumed it since it fit with the time they were president and had the same last name. I'm even more surprised that only 6% clicked that, I would think that a lot of non-Americans did not know this but maybe I'm wrong.