Question

Which element in "The Yellow Wallpaper" helps the reader better understand that the narrator is slowly losing her mind ?

Answer 1

C. Her obsession with wallpaper

Answer 2

The correct answer is:

C. Her obsession with the wallpaper

The idea is that the reader catches a persepctive that the narrator is slowly sinking into madness.  Is there really a woman creeping around outside in the bushes? Probably not. Is there really a woman trapped in the wallpaper? Definitely not. But is the pattern of the wallpaper interesting and confusing? Probably yes.