Answer:
This situation is an example of cross Price elasticity of Demand
Explanation:
If change in Price in Rental Company A doesn't necessitate change in prices in Rental companies B.C.D.E & F
Then the products A has on offer are not close substitutes to the rival companies
However where Rental company G lowers his price and it immediately triggers a Price reduction in Companies B to F, then obviously they offer similar products that are close substitutes and serve similar segment or channel of the Market Size. Thus failure to lower their Price will automatically see Customers rent cars more from Company G.
This situation is an example of cross Price elasticity of Demand