If a single large firm is able to produce a market's output less expensively than many small firms is evidence that, for this market, there are

a.constant returns to scale.b.increasing returns to scale.c.regulations in place that limit production costs.d.decreasing returns to scale

a.constant returns to scale.

b.increasing returns to scale.

c.regulations in place that limit production costs.

d.decreasing returns to scale.