Select the most appropriate option to complete the idiom in the given sentence.
I have been ________ over the two options in my head and I think we should go with the first one.

Correct option is B

The correct option to complete the idiom is (b) mulling.
The idiom "mulling over" means to think about something carefully and for a long time. This fits perfectly in the context of the sentence, where the speaker is contemplating two options.
Example: She spent the evening mulling over her decision to move abroad, considering all the pros and cons.
· Meanings of other options:
· Seeing: In the context of vision or understanding something clearly, not relevant to thinking or contemplating.
· Looking: Typically involves visually inspecting or searching, not suitable for describing thoughtful consideration.
· Obsessing: Implies a compulsive or fixated attention, which is more intense and less neutral than "mulling over."