Explanation:

- Price extension: Typically, this term isn't commonly used in economic frameworks related to pricing strategy. It could imply extending a product's price over time or regions but doesn’t capture the essence of varying prices across different buyers.

- Price contraction: This is not a standard term in pricing strategies. It might suggest reducing prices or narrowing price ranges, but it's not relevant to charging different prices to different buyers.

- Price discrimination: This refers to the practice of charging different prices to different buyers for the same product or service based on their willingness to pay, geographic location, or other factors.

- Price control: This involves government regulations imposing price ceilings or floors to control the maximum or minimum prices that can be charged for goods and services.