I chose option a.
Step-by-step explanation:
After Madame Loisel realizes the necklace is a fake and that she had been working for years to pay back the debt that she owed to several people for trying to buy a new one she is relived at first but slips into an unfortunate state of depression. While her husband recovers quickly he does not understand why his wife is so upset. She believes she has wasted ten years of her life doing something that wasn't necessary and wish she could take it back but she can't. Her husband leaves her claiming that he can no longer be with a depressed women because she is bring him down. The woman is now ever more unhappy and disappointed with herself. One month later and Madame Loisel kills herself. Her friend that she borrowed the fake necklace from comes into her home to find her dead the next day. The husband is contacted but he does not care for he married a rich woman and is very happy with his life. The end.
I hope this helps!