Suppose Canada produces only tablets and smartphones. The resources that are used in the production of these two goods are not specializedthat is, the same set of resources is equally useful in producing both smartphones and tablets. The shape of Canada's production possibilities frontier (PPF) should reflect the fact that as Canada produces more smartphones and fewer tablets, the opportunity cost of producing each additional smartphone . The following graphs show two possible PPFs for Canada's economy: a straight-line PPF ( PPF1 ) and a bowed-out PPF ( PPF2 ). Graph 1 TABLETS SMARTPHONES PPF 1 Graph 2 TABLETS SMARTPHONES PPF 2 Based on the previous description, the trade-off Canada faces between producing smartphones and tablets is best represented by .