Answer:
A. Sheila Kellar is considered by many to be the haughtiest girl in school.
Explanation:
The sentence above is using the superlative form correctly.
When we have a short adjective like "haughty", we need to add "est" to the end of the word to create the superlative form.
All the other 3 statements on the other hand, are using the superlative form incorrectly, because they are attaching the world "most" to short adjectives, and "most" can only be added to long adjectives like "delicious", or "beautiful".
