The answer is C. a stone monument
Hi I answered this same question a few weeks ago. I will try my best to find the paper so I can help you.
Blanche, by retreating into hysteria and madness, and by refusing to acknowledge her sister as she leaves the apartment with the doctor, may be sparing Stella the horror of having to face the truth about her husband. Blanche's descent into madness shields Stella from the truth.