8.7. A firm’s long-run total cost curve is Derive the equation for the corresponding long-run average cost curve, AC(Q). Given the equation of the longrun average cost curve, which of the following statements is true?

a) The long-run marginal cost curve MC(Q) lies below AC(Q) for all positive quantities Q.

b) The long-run marginal cost curve MC(Q) is the same as the AC(Q) for all positive quantities Q.

c) The long-run marginal cost curve MC(Q) lies above the AC(Q) for all positive quantities Q.

d) The long-run marginal cost curve MC(Q) lies below AC(Q) for some positive quantities Q and above the AC(Q) for some positive quantities Q.