TOEFL Reading: ETS-TOEFL阅读机经 - 65Y6D3G56LM8I5D6L$

According to paragraph 5, which of the following was one effect that the Navigation Acts had during the period from 1700 to 1760? A. They reduced the attractiveness of most locally produced commodities for the American colonists. B. They protected colonial merchants from having to compete with low-priced imports. C. They greatly increased the importance of the American colonies as purchasers of British exports. D. They raised the production costs for many commodities manufactured in the American colonies.