Question

“I don’t know where it came from,” he said mildly, “but I know for sure where it’s going.”

Answer 1

Because he said in a mildly motion, we can assume that he does not  take the dog away because he is cruel, he simply has like a good excuse to not keep it. But, his imperative tone of saying „I know where it is going” gives us the idea of he is not as comprehensive with the dog and it creates a problem in the story. With this explained, we can assume the best answer is C.