I tried it with the OP's sample input, and it favored Choice B - which seems entirely reasonable, since the last five words of the string are an exact match.
I agree, I think choice B is in fact the closest since the only word from the original string which is completely different is BROWN. FOX and COW have the O in common and the rest of the words match completely, while Choice C has two words which do not match at all.
At least as far as levenshtein distance goes, choice B is indeed the correct one, even if its not whats closest logically.
