Final answer:
Market collusion is exemplified by dividing markets, where firms agree on not competing in certain areas, akin to forming a monopoly, which is illegal in many regions including the EU and the US.
Step-by-step explanation:
When firms within an oligopoly collaborate to control prices or market shares, they engage in market collusion, which is illegal in many parts of the world including the European Union and the United States. An example of market collusion is A. Dividing markets, where firms agree not to compete in certain areas or to fix prices collaboratively, allowing them to act as though they were a monopoly and potentially enjoy monopoly-sized profits. This practice reduces competition and can harm consumers by keeping prices artificially high.