Another APEX Answer is:
Sometimes my heart was sinking so fast with anger, desolation, and weariness, I was afraid it would sink to the very bottom of the Pacific...(209)
Explanation:
Here Pi is fighting himself internally. He has depressing thoughts such as just giving up. He has a choice whether or not to act on those feelings which is the battle itself.
I'd say It demonstrates how Miss Fairchild's attitude changes from negative to positive when she recognizes Easton .
Thes best option from the given answers, would letter A.