Breaking a Monopoly Firm into Several Rival Firms Will Be

Breaking a monopoly firm into several rival firms will be unlikely to improve economic efficiency when economies of scale are important because

A) several smaller firms will have higher per-unit costs than a single larger firm.
B) a single firm will have higher per-unit costs than several smaller firms.
C) it is harder to regulate many smaller firms than it is one large firm.
D) consumers will find it harder to choose among the products of many alternative sellers.