Even If the Steel Industry Is an Oligopoly, There May

Even if the steel industry is an oligopoly, there may be more firms competing with the steel firms than you would think because

A) economies of scale exist
B) barriers to entry can be overcome
C) firms in other industries producing close substitutes may compete in the markets in which steel firms compete
D) economic profit lures other firms into the industry
E) there is high product differentiation