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"
The reason this answer is correct is because well first of all i took the test but second of all you should know a synonym is a different word same meaning of the other word chosen. So an antonym is the opposite of a synonym so the answer would be A-antonyms.
