A cost which has been incurred and cannot be recovered is called a:

The early U.S. canals and railroads were built by private enterprise without the aid of governments

Indicate whether the statement is true or false

Suppose an American worker can make 20 pairs of shoes or grow 100 apples per day. On the other hand, a Canadian worker can produce 10 pairs of shoes or grow 20 apples per day. When trade opens up, the United States should produce:

A. both goods, since they have an absolute advantage in both goods, and not trade. B. only shoes, since they have a comparative advantage in the production of shoes, and not trade. C. apples, since they have a comparative advantage in the production of apples, and not trade. D. only apples, since they have a comparative advantage in the production of apples, and trade for shoes.