A Natural Monopoly

A natural monopoly

A) typically arises because of a patent or copyright
B) is a firm that,due to economies of scale,can serve a market at lower average cost than two or more firm could
C) is a Pareto improvement as compared to a perfectly competitive market
D) enjoys diseconomies of scale,so average total cost falls as more output is produced
E) enjoys economies of scale,so average total cost rises as more output is produced