C would be your answer there due to it trying to help you visualize the setting
To fix him or beat him up his thinking
A topic sentence should make clear what the paragraph is about and express a view about the subject matter.
So, a possessive noun is usually used to indicate who or what has something, like "The Dogs' ball."
To change this form of children,plural, to a possessive noun, you will want to add an apostrophe, and then an s. It changes to this:
Children's