Milk has the sense of "taking", to milk something/someone. If you squander, you spend, give. If you exploit, you use, give. If you research, you collect info, take. If you hire, you employ, give (a job if you don't like the use of employ in this case). Wheedle, to influence, give. Answer C.
Okay. But take Merriam Webster's definitions, for instance:
1: to make productive use of : UTILIZE<exploiting your talents> <exploit your opponent's weakness> 2: to make use of meanly or unjustly for one's own advantage <exploiting migrant farm workers>
A farm hinges on racist debate and such, so let's switch the example to factory work.
If you build a sweatshop, pack it full of workers, and then pay them half of some minimum wage you could be looked at as cheating the workers. Also, minimum wage by definition could indicate illegal activity on your part.
How have you exploited the person though? Many time
I chose B at first as well. But upon more thought, I think (B) exploit:utilize does make more sense. To milk is by definition to extract, to draw something from an object or an animal.
To exploit is by definition to make use of, which is to utilize.
Although to research is to investigate. I think both milk:extract and exploit:utilize has more of the action of taking, where