Answer: The law of increasing opportunity costs
Step-by-step explanation:
The scenario given describes the law of increasing opportunity costs. This law explains that when there's an increase in output in the production of a good, this will then bring about a scenario whereby the opportunity costs of the additional units of the other good will then be less.
As there is an increase in the production of one good, then this will lead to the increase in the opportunity cost of producing the next unit.