10/10. Spelling bee champ of my county when I was in 6th grade. I didn’t make it to the state finals though. Boo.
10/10
I’d be pretty close even without the multiple-choice, since I almost always spell by visualization; I think of the look of a word and read it off. I’ve never seen #10, so I would have had to fall back on the roots-and-affixes method others have mentioned. (I had never seen ‘chiaroscurist’ either, but it’s a regular formation from ‘chiaroscuro’. No problem.) In any case, words based on Greek or Latin roots look Greek or Latin, so many spellings just never present themselves.
10/10. There were two words I’d never heard of, but the others were all okay. I actually use and read ‘autochthonous’ fairly regularly. I would suck at spelling bees, though, since my ability to spell is purely visual - I can write but I can’t spell out loud without writing it down first.
I did win the Spelling Bee, a few times when I was a kid. 
I cnt spl wrth crp, bt hv an amazg ablty 2 spt mispelins.
10/10, but pococurante and succedaneum would definitely have tripped me up in a real bee.
Won 4th grade bee with “derivative”.
Eliminated in 5th grade bee with the misspelling “accellerate”.
I’ve forgotten which grade this was (5th or 6th, maybe). In my spelling class, I had gotten 100% on all the year’s tests. But when I took the final test, one word was counted wrong because of my lousy handwriting.
I got ten, and knew eight of the words. Pisses me off we didn’t have spelling bees in Canada when I was a young 'un.
10/10 first try, probably couldn’t spell most of them unassisted though. Also, I think I’ve seen 6-7 of them before in reading, so that made picking them easier.
Tu hek with all tha arkayik spelling roolz. Go fonettik!
8/10, but I guessed on 2 of them. Fun!
10/10, and only 3 pieces of honeycomb?
But if not multiple choice I’d definitely have screwed up succedaneum. Or whatever it was.
Well, it is a spelling test, and not a math test.