If there is a higher tariff on British goods, then people would not want to buy their goods because the tax if too high. If they can get something else for a lower cost, such as good from American business then they would go and buy from those business. This protects them because again people like to get the most for their buck and this lessens competition from British business.
In the 1930 after a state of emergency was declared in Germany, was Field Marshall Paul von Hindenburg who took control of the government. So, the answer is D).
The Great plains, not sure why honestly.