The table below shows the late fees charged for overdue library books. A. The late fee is proportional to the days overdue because it follows the unit rate.

B. The late fee is not proportional to the days overdue because it has the same unit rate.

C. The late fee is proportional because the graphical representation would not be a straight line.

D. The late fee is not proportional to the days overdue because it does not follow a constant unit rate.