Willie Loves Ice-Cream Cones

Willie loves ice-cream cones. He has found a store that sells ice-cream cones at a bargain price of $0.50 each. He has just eaten two of these cones but has decided not to buy a third one. Which of the following statements best explains the zconomic principle at work in Willie's decision not to buy a third cone?

A) Consumers weigh the additional costs and benefits before buying more goods.
B) Consumers spend freely to increase business activity so that the price of goods will drop.
C) Consumers save more by buying larger quantities.
D) Consumers buy more at lower prices.