Answer:
Option C is correct.
Step-by-step explanation:
A. The number of points scored during a volleyball game with the time played, in minutes may not change constantly at the same rate.
B. The height of an acrobat flipping on a trampoline may not change constantly with time.
C. The price of bananas per unit weight must be constant at a certain place.
D. The outside temperature and the number of people going to the beach may not change at a constant rate.
Therefore, option C is correct. (Answer)
