Which sentence best describes the main idea of the news story? A. "A quick walk through any of the shopping districts of Buenos Aires will show the casual visitor many "No Coins" signs in storefront windows." B. "You do need to plan to spend extra time locating coins for many of your simpler purchases and exchanges." C. "If you hope to visit this beautiful, up-and-coming city soon, don't let the great Buenos Aires coin shortage stop you." D. "Lately, however, a bizarre problem has hit the city: it has become very difficult to make change."