Answer:
The correct answer is option A.
Explanation:
The association of De Beers and its affiliated producers is a cartel.
A cartel is formed by the producers in an oligopoly market, in order to protect their interests and earn higher profits. Forming a cartel is generally not legal in many countries. Cartels can be formed both formally and informally.
Members of a cartel can fix a higher price to earn more profit.