美国《连线》杂志主编克里斯·安德森归纳了长尾理论能够生效的三种力量，分别是（ ）。\n \n \n \n \n \n \n

\n \n \n \n A.\n 有人生产\n

\n \n

\n \n \n \n B.\n 有人购买\n

\n \n

\n \n \n \n C.\n 有人提供方便的信息\n

\n \n

\n \n \n \n D.\n 有人提供折扣\n