The answer is B: Less than a decade ago, the HSUS...an affiliate [Human Society International].
Brackets are used to give the writers (when they need to add information) an opportunity to add an explanation, or emphasis to a word, or change a <em>quote to fit to a sentence, but without changing the meaning of the text</em>. In A) <em>global work</em> doesn't need explanation; C) <em>decade</em> doesn't need explanation; D) <em>HSUS</em> was already explained in the first sentence of the text.
I have no idea what AP English 11 is like.
I think AP Bio is a difficult class to take. Bio may seem easy, but AP Bio is a whole different world. I would not recommend taking it unless you have a very good work ethic and you enjoy biology.
Don't take an AP class just to take one, choose one that you are intrested in.
