Answer:
The answer to your question is option C. The narrator believes that she was the woman behind the wallpaper.
Step-by-step explanation:
Other than for the story itself, we can conclude that this is the right answer because of the words used on the paragraph. The phrase I've got out at last shows that the narrator has escaped from something, and the word "last" at the end of the sentences expresses a sense of relief that she's no longer there, ruling out option A.
The phrase ..and I've pulled off most of the paper, so you can't put me back also shows that she is scared of that place and she does not want to go back, ruling out option B.
Finally, option D is not the right answer as the narrator implies that she was the woman behing the wallpaper all along when she says I've pulled off most of the paper, so you can't put me back! This means that she does not believe there's another woman like option D suggests, but does imply that she believes she was the woman behind the wallpaper. Therefore, the answer is option C.