The market is supplied by four firms. At $20, the market supply is 50 units and at $40 it is 100 units. The table gives each firm’s market share at those two prices. Which firm has no normal upward-sloping supply curve?
- A10% at $20; 10% at $40
- B20% at $20; 50% at $40
- C30% at $20; 20% at $40
- D40% at $20; 20% at $40