高階econ-u04-d05
Economies of scale exist over the range in which:
A. Long-run average cost falls as long-run output expands✓ 答案
B. Long-run average cost rises as soon as output expands
C. Long-run average cost always equals marginal cost
D. Short-run total cost becomes variable
解說
Economies of scale come from specialisation, better technology and spreading overheads, so the falling portion of LRAC is the economies-of-scope range. Diseconomies appear later as coordination costs grow.