For the Fall semester, you had to pay a nonrefundable fee of $600 for your meal plan, which gives you up to 150 meals. If you eat 100 meals, your marginal cost of the 100th meal is:

For the Fall semester, you had to pay a nonrefundable fee of $600 for your meal plan, which gives you up to 150 meals. If you eat 100 meals, your marginal cost of the 100th meal is:
A.$0.25.
B.$0.
C.$4.
D.$6.
正确答案：$0.