Answer: B) Children are used to working in unfair conditions.
Explanation: The setting of a story or a text is the place and time where the story takes place, it can also be the context of the story (political, historical, cultural, etc). In the given excerpt we can see that that the children are used to working in unfair conditions, because of the way that Khan treated them, and the fact that they had to work with a shackle on their ankles, as they were prisoners.