How does air from air-conditioning vents affect open display cases? Select one: A. It improves their performance by lowering the temperature of the air surrounding the display case. B. It disrupts the case's air curtain, causing them to rise in temperature. C. Open display cases are not affected by external air sources because of their powerful built-in air curtains. D. Open display cases are not affected by external air sources because of their engineered air baffles. Clear my choice