Based on what we know of Mathilde, what makes her heart "throb with an immoderate desire" when she sees the necklace in the black box in section 43 of "The Necklace"?
A. Mathilde thinks the necklace is made of diamonds and will make others think she is rich.
B. Mathilde thinks the diamond necklace would be the thing her friend could spare the most.
C. Diamonds are her birth stone.