Iago gives several reasons for his hatred of Othello (usually to his confidant Roderigo). He says that he hates Othello because Othello passed him over for a promotion to lieutenant, choosing Michael Cassio (who he claims is much less qualified) instead of him. He also claims that he suspects that his own wife, Emilia, has cheated on him with Othello, making him a cuckold. However, it is unclear whether either of these are the real underlying reason for Iago's hatred—this is never completely clarified by Shakespeare.
The correct answer is A. The student is associating two things together, Bob and the word "obnoxious." Therefore, when she comes into contact with either, she will be reminded of the other.
I think the answer is B) The students could not hear the bell ring in the cafeteria. If the arguement was hard to ignore, then they probably couldn't hear the bell.