Which novel involves a character experiencing a breakdown after childbirth?

The correct answer is "The Yellow Wallpaper." This novel, written by Charlotte Perkins Gilman, explores the mental health struggles of a woman undergoing the pressures of postpartum confinement. The protagonist is subjected to a "rest cure" by her husband, which involves isolation in a room with oppressive yellow wallpaper. As the story progresses, she experiences a profound psychological breakdown, which is intricately tied to her experiences of motherhood and societal expectations.

The themes of mental illness, the constraints placed on women in the 19th century, and the impact of motherhood on identity are central to the narrative, making this work a crucial commentary on women's rights and mental health. The vivid description of her descent into madness, exacerbated by the confinement, serves as a powerful critique of the treatment of women's mental health during that era.

While the other options include significant literary works, they do not focus primarily on the theme of a character's breakdown following childbirth in the same way that "The Yellow Wallpaper" does.