"A" is the correct choice :)
Him.
If you don't know how to solve this, you can put each word in to the blank and see which sounds right.
I think the answer would be C.
Maybe review over the text it’s talking about. I would help but there is not text for what you are needing help with. Try putting a photo of the text your questions are linked to? Then it would be easier to help with what your asking.