题目

Money spent on advertising is money spent as well as any I know of. It serves directly to assist a rapid distribution of goods at reasonable prices, thereby establishing a firm home market and so making it possible to provide for export at competitive prices. By drawing attention to new ideas it helps enormously to raise standards of living. By helping to increase demand it ensures an increased need for labor, and is therefore an effective way to fight unemployment. It lowers the costs of many services: without advertisements your daily newspaper would cost four times as much, the price of you一个数的倒数是它本身的数是 [     ]A．1 B．-1C．±1 D．0