Answer: The adverb clause in this sentence is "so that we can go to the basketball game". It explains the main verb "write" more thoroughly, and gives us an explanation "why" they have to do finish their composition.
Explanation: Adverbial clauses of purpose introduced by "SO THAT" are always followed by a modal expression such as CAN, WILL, COULD, etc.
I would B because it's the only thing that makes sense. One would hope that debacle would be down (and in 2020, it was up) as well as discontent, and rhetoric doesn't make sense in this sentence.
