the 3rd one, even the smartest people need help sometimes
Explanation:
Allegra claimed to be too smart for getting help from a little girl but she actually helped Allegra so its pretty obvious and the hint sentence in this paragraph could be "thanks to some assistance from a young girl"
The passage is telling us that no matter how smart you are, even a little help from anyone can benefit you, even if you think you don't need it. Such was the case with Allegra.
And it best describes the main theme of the story.
