怎么区分rivarlry和substitute？

问题如下：

1. Using Porter’s five forces analysis, which of the following competitive factors is likely to have the greatest impact on Omikroon’s petrol scooter pricing power?

选项：

Rivalry

Threat of substitutes

Threat of new entrants

解释：

B is correct.

Inexpensive, small imported motorcycles are substitutes for petrol scooters and may increasingly have an impact on Omikroon’s petrol scooter pricing power.