I believe you have a typo when it comes to the first option - it should be athletics, not athletic. The word athletic is an adjective, and the word athletics is a noun.
That being said, the correct answer is A. athletics. Even though this noun ends in -s, it is still singular. The rest of the options are all plural nouns.
A thesaurus is the correct answer
I would say D because it gives an answer with sequence and follows along with the other points such as
-first
-second
-third
-? (fourth)
-finally
If we are referring to academic vocabulary, we mean to say the words or group of words that are used in the academic dialogue. These words are not common and are not frequently encountered in daily conversations. We can change the word awful to dreadful.
Pretty sure the answer is a!!!:)