For questions 3-5, choose the letter of the diagram in figure 2.1 that best describes the type of shift that would occur in each situation for the U.S. automobile market, ceteris paribus. Figure 2.1 Supply Curve Supply Curve Demand Curve Demand Curve (leftward) (rightward) (leftward) (rightward) Price Price Price Price Quantity Quantity Quantity Quantity (a) (b) (c) (d) OPEC lowers oil prices, which causes a significant decrease in the cost of gasoline for vehicles. O a Ob O c Od