Answer:
D) The amount of real capital used per worker has increased historically in the United States.
Step-by-step explanation:
In the economy, real capital is any good applied to the creation of supply of new goods or services. It is not limited, therefore, to the money invested. In short, real capital is a term that refers to the use of a good to offer goods and other goods. In recent years the US economy has grown significantly and this has reflected in the supply of goods and services and consequently in the real capital of the country, so we can say that the amount of real capital used per worker has historically increased in the United States. .