题目

阅读理解Should I stay or should I go? An LED device(设备) for driverless cars aims to give pedestrians(行人) at a crossing the power to communicate with cars, signaling for them to stop or drive on. Blink, created by researchers at the Royal College of Arts and Imperial College London, turns the awkward dance of eye contact and hand gestures that happens when a car slows down while someone is waiting to cross the road into something driverless cars can understand. Blink combines an organic light display with the windscreen(挡风玻璃) and windows of a car and uses light signals to sh下列运算中，错误的是（       ）A．B．=-C．D．=-1