Suppose That a Firm's Total Cost of Producing an Output

Multiple Choice

Suppose that a firm's total cost of producing an output of 400 units a day is currently $2,000.If technology and the price of inputs remain unchanged,what level of output would be produced if total cost rises to $4,000 and increasing returns to scale exist?

A) 5 units.
B) More than 400 but less than 800 units.
C) 800 units.
D) More than 800 units.