Answer:
b) She felt entitled to riches because of her looks.
Explanation:
Madame Loisel, as can be inferred from the paragraph, is not born in a wealthy family, but certainly possesses great beauty and charm. The statement, "She dressed plainly because she could not dress well, but she was unhappy as if she had really fallen from a higher station;" indicates her dissatisfaction with her humble situation, the sorrow of which she feels as though it were a step-down from a "higher-station."
Here, "higher-station" cannot be a major change in her financial situation after marriage, because she was born in a family of clerks and subsequently married a clerk. It, however, suggests that she felt that she was entitled to more than what she got, and that her not being able to dress well, or have luxury in a way, was like a step-down from what she deserved because of how she looked.