Final answer:
The correct feature included in NAFTA is the elimination of tariffs on trade among Canada, Mexico, and the United States, thus answer b. II is correct.
Step-by-step explanation:
The feature included in the North American Free Trade Agreement (NAFTA) is the elimination of tariffs on trade among Canada, Mexico, and the United States. Therefore, the correct answer is b. II.
NAFTA was a trade agreement between Canada, the United States, and Mexico that eliminated many trade barriers, including tariffs, quotas, and taxes, and allowed goods to flow more freely between the three countries. However, it did not create a common tariff structure for external countries, nor did it provide for the free mobility of labor and capital among the nations.