Ssocial Sprivate Price of steel Dprivate Q2 Q1 Quantity of steel Exhibit 8-2 Refer to Exhibit 8-2. Which of the following observations is correct? O a. The equilibrium at P2 and Q2 is inefficient. O b. The equilibrium at P1 and Q1 is efficient. O c. From society's standpoint, Q1 is the efficient level of output. O d. The social opportunity cost is above the demand curve at Q1