If an Industry's Long-Run Average Total Cost Curve Has an Extended

If an industry's long-run average total cost curve has an extended range of constant returns to scale, this implies that

A) technology precludes both economies and diseconomies of scale.
B) the industry will be a natural monopoly.
C) both relatively small and relatively large firms can be viable in the industry.
D) the industry will comprise a very large number of small firms.