What is minimum efficient​ scale? Minimum efficient scale is
A. the level of output at which a firm begins to experience economies of scale.
B. the level of output at which all diseconomies of scale are exhausted.
C. the level of output at which the​ long-run average cost of production begins to decline.
D. the level of output at which all economies of scale are exhausted.
E. the level of output at which the marginal cost of production reaches a minimum.