The correct answer is D) What happens is different from what the characters expected.
In "Charles" by Shirley Jackson, the model thinks that the "Charles" her son is talking about is a real boy who is also a bad influence for his son. yet she discovers at the end that Charles had been invented by her son to deflect blame for his own misbehavior. In "The Gift of the Magi" by O. Henry, both spouses sacrifice something very valuable for each other in order to buy gifts that reveal themselves to have been rendered useless by their loving gesture (the wife no longer has long hair for the expensive combs her husband buys her and the husband has sold the watch for which his wife sold her hair in order to get him a new fob chain). "The Necklace" by Guy de Maupassant, Mme Loisel and her husband ruin themselves for ten years to pay for an expensive necklace a wealthy friend let her borrow for a party only to discover that the said necklace was in fact a cheap knockoff. In all three stories the ending was completely unexpected both for the characters and the readers.