When Harry took a library book home without checking it out, he was merely given a warning by the librarian. However, when Ron did the same thing, his library privileges were suspended for a month. Harry's actions were revealed when he returned the book to the library, and the librarian noticed that it had never been properly checked out. Ron's action came to the library's attention when his younger sister set the book on fire, and their parents forced her to repay the library from her allowance. Although
the book Ron took was destroyed and the book Harry took was unharmed, the damage was caused by Ron's sister, so the difference was not due to a difference between Ron's and Harry's behaviors. Therefore, Harry should also have had his library privileges suspended.
The bolded phrase plays which of the following roles in the argument above?
A. It provides evidence directly supporting the conclusion of the argument.
B. It identifies a possible objection to the conclusion, to which the author then responds.
C. It summarizes the reasoning offered by an opponent of the argument.
D. It provides unrelated information not relevant to the argument.
E. It provides information proving the falsity of the conclusion.
How to approach these kind of questions?