C. it provides evidence for the reader
I think the answer is B.
Because it sounds more proper and it's saying Dickens and then HE wrote the novel and then it says what he wrote about.
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.
It is a metaphor for troubles and hard times. He says that these "clouds" are now gone, and this is due to the fact that "the winter of his discontent" is over, due to the joyous reign of king Edward IV.
