C. rises; decreases
If the price of a substitute good rises, the demand for a good decreases.
The “exchange” introduced a wide range of new calorically rich staple crops to the Old World namely potatoes, sweet potatoes, maize, and cassava. The primary benefit of the New World staples was that they could be grown in Old World climates that were unsuitable for the cultivation of Old World staples.
Advertising a product changed from simply announcing the existence of a product in a dull, dry fashion to persuading the public they needed and deserved to own the product. By developing repeat customers, advertising also helped build brand loyalty for the company.
Answer:
Build a powerful militiary in Europe