Answer:
A) Antonyms
Explanation:
In the case of the sentence "Although Amelia was quite lithe, her sister was clumsy and awkward" the unknown word is "lithe" and this is mainly explained by the conjunction "Although " and "her sister was clumsy and awkward" that shows the word "lithe" is the opposite of "clumsy" and "awkward" and indeed "lithe"
Your answer will be:
They arrive at the perfect moment to make Framton believe them to be ghosts.
-PJ