Once a Cartel Determines the Profit- Maximising Price

Once a cartel determines the profit- maximising price,

A) entry into the industry by rival firms will not affect the profit of the cartel.
B) changes in the output of any member firm will not affect the market price.
C) each firm faces the temptation to cheat by lowering its price.
D) each firm faces the temptation to cheat by raising its price.