for
with
on
in
Answer is Wrong!
Answer is Right!
The correct answer is B. with.
The word “obsessed” means to be dominated by an idea or feeling. In this sentence, the speaker is saying that they are not dominated by such ideas as the listener is. The word “for” is used to express a reason or purpose. The word “on” is used to express a location or position. The word “in” is used to express a state or condition.
In this sentence, the speaker is not expressing a reason, location, or state. They are expressing a lack of domination by an idea. Therefore, the word “with” is the most appropriate choice.