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.
The question is vague. Which works are you referring?
It is a because swarm in singular in this case. The whole group acts as one. As a collective noun, swarm can be plural, but only if each bee were doing something individually.
