The sentence that best shows the difference between Madame Loisel and the other guests at the ball is:
B. “He threw over her shoulders the wraps he had brought, the modest wraps of common life, the poverty of which contrasted with the elegance of the ball dress.”
This sentence highlights the stark contrast between Madame Loisel's modest background and the opulence of the ball, emphasizing her feelings of inadequacy and desire for a life of luxury compared to the other guests.