Madame Mathilde Loisel selects what she thinks is a diamond necklace because she believes it is "superb" and just the kind of dazzling jewelry that will enable her to attract the attention of the male guests and make her appear affluent.
B - It can leave the reader unsatisfied
An anticlimax is a disappointing (or unsatifying) ending to an otherwise exciting series of events. Example: think of an action movie that just ends without wrapping up the loose ends or leaves too many unanswered questions.
I think Body would be your answer