If the Average Total Cost of Producing 20 Sweaters an Hour

Multiple Choice

If the average total cost of producing 20 sweaters an hour falls when the firm doubles all its inputs, then the

A) short-run average total cost curve shifts upward because all inputs have increased.
B) firm moves along its short-run average total cost curve.
C) firm experiences economies of scale.
D) long-run average cost curve shifts downward.