When Members of an Oligopolistic Industry Agree to Collude, Raising

When members of an oligopolistic industry agree to collude, raising their product price substantially above average cost, the passage of time (months and years)

A) is usually needed for the members to solidify their cooperation.
B) usually results in finer control of prices and markets by the group and larger profit margins.
C) is likely to erode the agreement, as ways to cheat are developed by some participants and new entry is encouraged by the high price.
D) seldom has any impact on the agreement, as long as the participants maintain high profit levels as a result of the agreement.