Here are several economic events that could potentially help trigger a recession. Say which category each one falls into: negative supply shift, negative demand shift, inflation fighting, or problems in financial markets. a) War in the Middle East destroys oil fields in Saudi Arabia. b) China suddenly cuts off exports to the United States. c) Inflation accelerates sharply to 10 percent a year. d) Mortgages become much harder to get because banks become less willing to lend.