Differential Rent and the Different Types of Income

Rent is extracted from surplus value because land owners don't produce value. Differential rent is rent that's set by the price of production on the market. Prices tend towards the highest price of production, it's set by people who are worse to producing it. And differential rent is the rent that the rest of the market gets by costing it less for them to extract oil than it does for someone who's like the worst at extractingOil.