Answer:
The answer is: C) price fixing
Step-by-step explanation:
Price fixing is an illegal agreement between a group of buyers or sellers, only buyers or only sellers, of a certain product (or products) that decide to buy or sell that product only at an specific price.
Price fixing is usually done by businesses that sell certain products or services, that form cartels to try to control the price. One of the most famous and most powerful international cartels is the Organization of the Petroleum Exporting Countries (OPEC).
They don't control all the production and selling of oil in the world, but they control a very significant portion of it. So by joining together they can increase the international price of oil by reducing the production levels from its members.
They are so powerful that no one even cares that what they do is illegal, they are too rich for the law to apply to them.