According to William Shepherd's Examination of Competitive Trends in the U.S.economy,the

According to William Shepherd's examination of competitive trends in the U.S.economy,the industry of a firm that faces no or very little competition and contributes more than 50 percent of the market supply _____

A) is usually a pure monopoly.
B) is a dominant firm.
C) is a tight oligopoly.
D) is effective competition.
E) is monopolistic competition.