Answer:
C
Step-by-step explanation:
Cartels are difficult to maintain because there is always a tension between cooperation and self-interest in a cartel.
There is always the temptation that selfish tendencies develop amoung cartels and tha ability to cooperate becomes more difficult. Take for example OPEC is the best know example for an international cartel. Presntly Russia and Saudi Arabia are at logerheads over production of oil. Instead of them to stick within the rules of how much oil can be oroduced in a day, because of their selfish interest some of them want to produce more . This becomes difficult to maintain