What does this except from the end of yellow wallpaper tell the reader about?

B) The narrator believes that she was once behind the wallpaper herself.

Explanation:

In the given excerpt from "The Yellow Wallpaper" we can see the description of how the narrator doesn't like to look out of the windows because she sees creeping women. From the given options, the phrase that tells the reader about the narrator's mental shift is "The narrator believes that she was once behind the wallpaper herself" we can see this when she says " I wonder if they all come out of that wall-paper, as I did?"

The claim.

Explanation:

Let's look at what the sentence does.

"Topic [x], [y], and [z] are factors of [z]."

This is not a reason, as it doesn't attempt to explain anything.

There is no proof in the sentence itself, so it cannot be evidence.

It does not counter a previously made argument, it just sets forth a new claim - so your answer is A. The statement is a claim.