Executives at Leonesse Cellars, a premium winery in Southern California, were surprised to learn that shipping wine by sea to some cities in Asia was less expensive than sending it to the East Coast of the United States by road, so they started shipping to Asia. Because of the large U.S. trade deficit with major Asian countries, cargo ships from Asian countries arrive at West Coast ports fully loaded but return half to completely empty.

Use the concept of opportunity cost to help explain why shipping to Asian cities on these cargo ships returning to those cities would be cheaper than shipping by land to the East Coast of the United States. You must give an explanation.