The Long-Run Average Total Cost (LRATC) Curve

The long-run average total cost (LRATC) curve

A) indicates the per-unit cost of producing various rates of output with a specific size of plant but variable levels of labor and technology.
B) indicates the minimum per-unit cost that can be achieved at various output rates when the firm is free to choose among plant sizes.
C) will be falling when diseconomies of scale are present and rising when economies of scale are present.
D) is a U-shaped curve.
E) is both a and d above.