Which of the following statements is true? Group of answer choices The opportunity cost of producing a good increases as we produce more of the good. In economics, "law" means "empirical regularity", which is something that we observe that happens "very rarely" in real life. When the economy is operating on the PPF (it is being efficient), the only way to get more of one good is to give up some of the other because all resources are already being used. All of the above. Only a) and c)