A local restaurant offers an "all you can eat" Sunday brunch for $12. Jenica eats two servings but leaves half of a third helping uneaten. Why?

A. Her marginal value of brunch has fallen below $12.
B. Her marginal value of additional food has fallen below $4 ($12 divided by 3 servings).
C. Her marginal value of an additional bite of food has fallen to zero.
D. The total value she places on brunch today exactly equals $12.