Final answer:
The main struggle of Mme. Loisel is characterized by an internal conflict, as she battles her own desires to be part of a higher social class, which is unattainable for her.
Step-by-step explanation:
The main conflict that captures Mme. Loisel's struggle in the story is B. Internal Conflict; her wanting to belong to a social class that is out of reach. This type of conflict is known as an internal conflict because it deals with Mme. Loisel's dissatisfaction with her own social standing and her longing to be part of a higher social class, which causes her much personal anguish and shapes her motivations and actions throughout the story. The anguish experienced by Mme. Loisel comes from within herself, as she grapples with her aspirations and the reality of her life.
Conflict in literature can be either internal, occurring within a character, or external, caused by outside forces. In this case, Mme. Loisel's conflict is not about struggling against another person's expectations (external conflict), but rather her own desires and perceived shortcomings (internal conflict). Thus, option B aligns with the notion that the core tension in the story is an internal struggle and not based on external forces such as other characters' desires or social pressures, although they may contribute as secondary elements.