The correct answer is C.
A does not make sense as it "blocks" the whole section of choices.
B does not make sense either, it is trying to place parenthesis where no emphasis whatsoever needs to be given.
D is wrong because of the same things that are wrong with B.
C is correct because it correctly separates the letter choices from the answers, giving information with the correct context.
prefix is anti
prefix meaning is against
I believe it is A. It seems the most logical. I imagined her voice in my head to be pretending excitement and then when talking to the professor, a tired, authentic demeanor. Hope this helps!