In the table below, all other things being equal, which combination of factors A, B, C or D is most likely to enable an incumbent firm in an oligopolistic market to successfully defend its market share against new, low-cost entrants?
| Price elasticity of demand for the firm's brand | Level of consumer switching costs | Long-run average cost subject to | |
|---|---|---|---|
| A | Low | High | Economies of scale |
| B | High | Low | Diseconomies of scale |
| C | Low | Low | Diseconomies of scale |
| D | High | High | Economies of scale |
A
B
C
D
