Suppose a firm is producing in the long run. When it produces 2,000 units of output, its total cost is $4,000. When it produces 2,300 units of output, its total cost is $4,100, and when it produces 2,600 units of output, its total cost is $4,200.
This firm is experiencing (constant, decreasing, increasing, increasing then decreasing, decreasing then increasing) returns to scale.?