Four firms supply 85% of a market and closely monitor one another's prices. Which conclusion is most accurate?
The market must be perfectly competitive
The market is a monopoly because one firm may be largest
The market is likely to be an oligopoly because a few firms dominate
The market cannot contain barriers to entry
28 exam-style questions on OCR GCSE Economics 2.5 Competition, covering 2.5.1 Why producers compete, 2.5.2 How competition affects price, 2.5.3 Economic impact of competition, and 2.5.4 Monopoly and oligopoly. Each one has a worked solution and a mark scheme showing where the marks go.