A Study of Japan's Opening to Trade in 1859 Showed

A study of Japan's opening to trade in 1859 showed that international trade increased the per capita income of Japanese. Why does Japan, in this case, offer an excellent "natural experiment"?

A) Japan chose to have open trade in order to grow unlike other most other countries, so that it can be argued that the trade had the best chance to occur without being resisted by the government.
B) Japan adopted open trade because of a conversion by its Tokugawa rulers to free trade, who allowed open trade to occur naturally without government interference.
C) Japan only traded with the United States, allowing for a clear delineation of how it benefited from trade.
D) Japan moved from having almost no trade to having open trade with the world and this move was not due to economic reasons.