Final answer:
No, the situation described is not proportional. Proportional relationships occur when two quantities have a constant ratio. In this case, the cost of the cup is $3 and the cost of refills is $0.
Step-by-step explanation:
No, the situation described is not proportional. Proportional relationships occur when two quantities have a constant ratio. In this case, the cost of the cup is $3 and the cost of refills is $0. Since the cost of the cup does not change and the cost of refills is always $0, the ratio of the cost of the cup to the cost of refills is not constant. Therefore, it is not a proportional relationship.