Answer:
I believe the best answer choice for the question, would be, B: Subject matter.
Explanation:
The reason why I believe this is the best choice is because throughout the quote, the pronoun "it" is used, first in brackets, which emphasises the importance of placing that particular pronoun there to clarify what the quote is talking about, and then later on this pronoun is repeated, as if returning the focus on the subject itself. Throughout the reading you ask inevitably who the subject is. That is why I believe the best choice is B.
