An oligopolist differs from a perfect competitor in that
A) the market demand curve for a perfectly competitive industry is perfectly elastic but it is downward-sloping in an oligopolistic industry.
B) there is cutthroat competition in perfect competition but little competition in oligopoly because firms have significant market power.
C) there are no entry barriers in perfect competition but there are entry barriers in oligopoly.
D) firms in an oligopoly do not produce homogeneous products while firms in perfect competition do.