高階ECON-PRDC-019
Economies of scale mean that, as the firm’s scale increases in the long run:
A. Long-run average cost falls.✓ 答案
B. Short-run marginal cost must rise at once.
C. The firm’s demand becomes perfectly inelastic.
D. Fixed cost disappears from every short-run calculation.
解說
Economies of scale are a long-run average-cost concept: a larger scale has a lower cost per unit. They are not the same as diminishing marginal returns, which is short run. Demand elasticity is a market fact, not the definition.