The climax of "The Yellow Wallpaper" occurs when the narrator reveals that she identifies herself completely with the woman trapped underneath the wallpaper. Option A is correct.
In a story, climax is the term employed to refer to the part of story or play where the tension or action reaches its highest part. Sometimes, the climax is a "crisis" point in the plot.
"The Yellow Wallpaper" is a short story by American writer Charlotte Perkins Gilman considered an important early work of American feminist literature.