As the Number of Sellers in an Oligopoly Increases

As the number of sellers in an oligopoly increases,

A) output in the market tends to fall because each firm must cut back on production.
B) the price in the market moves further from marginal cost.
C) collusion is more likely to occur because a larger number of firms can place pressure on any firm that defects.
D) the price in the market moves closer to marginal cost.