When a Firm Operates at an Output Level of 9,000

Multiple Choice

When a firm operates at an output level of 9,000 units, the per-unit cost is $5. When the production is between 10,000-12,000 units, the per-unit cost is $4. At a production level of 13,000 units, the production cost is again $5 per unit. At 14,000 units and above, the production cost increases further. At what output level does the firm experience economies of scale?

A) 9,000 units
B) 11,000 units
C) 13,000 units
D) 15,000 units